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Posts tagged “Lumiere Technology

Fake or Fortune: Hypotheses, Claims and Immutable Facts

We have received two communications on “La Bella Principessa”, which drawing some take to be by Leonardo da Vinci. One came from the work’s owner, the other from a disinterested scholar in confirmation that the work could not, for reasons of arithmetic and plain physical facts, have been made by Leonardo for inclusion in a book.


Above, Fig. 1: The full vellum sheet of the proposed Leonardo drawing “La Bella Principessa”.


This drawing was presented anonymously to the world in 1998 without authorial ascription and without an atom of provenance. When claims of autograph Leonardo authorship were made after barely a decade, it became necessary to fill a five-hundred years long void of records in order to dispel suspicions of forgery or pastiche. In 2010 Professor Martin Kemp bundled together what he held to be a “barrage of evidence – stylistic, historical or technical” that somehow provided collectively what no individual parts constituted: proof that Leonardo da Vinci was the author of what he (Kemp) dubbed “La Bella Principessa”. Thus, a collection of not-evidence was vested with quasi-evidential force on a circular, question-begging appeal to the claimed authority of a “sustained, collective sense that the portrait ‘belongs’ to Leonardo and contributes something new to the Leonardo we currently know.”

Although some scholars (chiefly Italian) were persuaded by the claims, for the consensual majority who did not see Leonardo’s hand in the drawing, Kemp’s methodological ju-ju gained no traction. His claims were advanced in a portmanteau book of collective advocacy, La Bella Principessa – The Story of the New Masterpiece by Leonardo da Vinci, which he co-wrote with Pascal Cotte of Lumiere Technology (the firm hired by the drawing’s owner, Peter Silverman, to conduct technical research) and which carried highly supportive contributions by Peter Paul Biro, Eva Schwan, Claudio Strinati and Nicholas Turner; London, 2010 (– see pp. 187-88).


During Pascal Cotte’s technical analysis of the drawing it was noticed that three holes are present on the left-hand edge. Cotte took these to “prove that it originally came from a book or a manuscript” (- Kemp/Cotte 2010, p. 113). Working with Mr Cotte, Prof. Kemp proposed that the hypothetical book might well have been a collection of celebratory poems of Bianca Sforza who had died in childhood and that “La Bella Principessa” had been made as an illustration to such a book.

Above, Fig. 2: “La Bella Principessa” with Pascal Cotte’s indicated locations of the three supposed stitch holes.

Kemp’s elaborate hypothetical advocacy constituted a daisy-chain of improbabilities. This is a drawing made in the manner of a distinctive (and invariably painted) profile portrait type that is nowhere encountered in recorded Leonardos – and, indeed, this is the very type which Leonardo famously subverted with his own revolutionary plastically dynamic figural innovations. Within the rigorous constraints of the strict profile type, this drawing’s supposedly high-born subject is bereft of the customary/requisite opulence in clothing and jewellery. The eccentric iconography was made on an atypical support – vellum. It was drawn, Kemp holds, either directly from the subject in celebration of her wedding, or, as a commemorative portrayal after her death and thus made either in recollection or from some other depiction. No explanation was offered for how this single image might have resulted from two radically different circumstances of execution.


On a suggestion from Professor David Wright, Kemp proposed that this from-life or post-death portrait had been made to be incorporated within a large, heavy book of the mid-1490s that is now housed in Poland, the so-called Warsaw Sforziad. In the wake of a great deal of (Kemp and Silverman-activated) archival research which found no mention of any work resembling “La Bella Principessa”, it can be seen that without this claimed Warsaw connection, the drawing would remain what it was on its 1998 debut: a stylistically untypical and unprecedented work without any history – the inclusion of which within Leonardo’s oeuvre would, in Prof. Kemp’s own advocacy, “contribute something new to the Leonardo we currently know” and “reveal a previously unknown dimension to the way in which he fulfilled his duties at the court of Duke Ludovico Sforza”. (Kemp/Cotte, 2010, p. 188.) Without history, that is to say, other than the time it is now said to have been in the possession of the restorer/painter Giannino Marchig, the late husband of the anonymous vendor in 1998.

It has been claimed many times that a ‘match’ exists between the drawing’s holes and the book’s stitches but, aside from the small format photo-diagram at Fig. 3, this has never been demonstrated or independently corroborated. Similarly, it has been said that carbon dating tests established that the vellum sheet on which the drawing was made is of an age securely consistent with a drawing being made by Leonardo in the mid-1490s. This claim is seriously misleading, as is shown below.


Before Prof. Wright’s suggestion, in 2010 Pascal Cotte regarded the three holes on the drawing’s left-hand edge as evidence that might identify incorporation within a specific book:

“It would be interesting to use the evidence of the nature and placement of these needle holes to look for other surviving quires from the same codex, which, with other physical clues, might shed further light on the provenance and original commission.”

(Kemp/Cotte, 2010, page 113.)

Cotte’s hope was reasonable but such testimony can cut both ways. Establishing a relationship between the drawing and a particular book requires an exact correspondence between the drawing’s holes and a book’s stitches. Two separate claims were made of a discovered fit with the Warsaw Sforziad, first by the drawing’s owner, Peter Silverman, and then jointly by Martin Kemp and Pascal Cotte. Both occasions were filmed by National Geographic but only the second was broadcast. In it, Kemp expressed himself as being 80% confident. The presently claimed location of the drawing is at the front of the Sforziad. Clearly, the credibility of what is now a 200 million euro-insured drawing that is stored in the Geneva Free Port depends greatly on confidence being maintained in this claimed connection.

Above, Fig. 3: A facsimile of “La Bella Principessa” inserted into the Warsaw Sforziad with five arrows marking the
book’s stitches and three circles in which matches are claimed, but are not evident, between the drawing’s holes and
the book’s outer and central stitches. (The stitch marked by the right-hand arrow is shown in close-up below at Fig. 5.)

As previously shown, our colleague in ArtWatch, Dr Kasia Pisarek, has catalogued very many discrepancies between the drawing and the book, the most problematic being that the former has only three stitch holes, when the latter was bound with five stitches. To cope with this material/arithmetical incompatibility, Kemp and Cotte conjured two hypotheses.

The first was that the book had originally been bound with only three stitches and that at some undated point the drawing had been removed during a rebinding in which two extra stitches were added to the book. That (unsupported) contention was technically implausible: the book is too large and heavy to be supported by just three stitches – and
both of its sister volumes in London and Paris were bound with five stitches.

The second, and now preferred, hypothesis is that the book was indeed originally bound with five stitches and that, as
a part of this book, the drawing originally possessed the requisite five stitch holes, two of which had subsequently been cut off from the sheet. We demonstrated the impossibility of that claim in an earlier post. (To recap briefly: as Cotte had acknowledged in 2010, stitch holes are always made in a straight line along the crease in a group of folded sheets. Given that a central and two outer stitch holes are all present on the “La Bella Principessa” sheet, any original intermediary stitch holes would necessarily be found in alignment with the present three holes on the sheet as it is today.)

In addition to the absence of the two requisite stitch holes, the sheet itself is a mismatch in terms of colour, texture and size with the sheets in the book. Kasia Pisarek now adds a further mismatch:

“The follicles in the ‘La Bella Principessa’ vellum are tightly spaced, while those in the Sforziad vellum are widely spaced. This can be seen on the Polona website, where you can zoom in until you can see the follicles as dots. I remember seeing some pages where the dots were more apparent and they were definitely widely spaced.”


Yet another unaddressed difficulty concerns the back of the drawing. One of the earliest proponents of a Leonardo ascription, Dr Cristina Geddo, has described the presence on the reverse of the drawing of random lettering and an image of a dragon. Kemp and Cotte seem not to have offered an explanation for this content (which, presumably, was revealed by Cotte’s penetrative photography) even though they now claim that the back of the drawing would have faced the book’s beautiful and elaborately painted, symbolically-charged frontispiece. What conceivable iconographic function might such a melange have served in that strategic context of so important and precious a book? Dr Geddo has called for the vellum drawing to be removed from its (most unusual) oak panel support but the owner has declined to do so on grounds of safety. Some of the lettering is visible in an X-ray photograph published in the 2010 and 2012 English and Italian editions of the Kemp/Cotte joint book.


As we reported previously, with regard to the Three Holes v. Five Stitches conundrum, the problems for supporters of “La Bella Principessa” have now become insurmountable: Pisarek established on her second examination of the Warsaw Sforziad in the Polish National Library that while the drawing bears only three holes, the book itself was not only bound with five stitches but that each of those stitches passed through two holes that were two or three millimetres apart (see Figs. 6, 7 and 8 below). At a stroke, the previously claimed ‘fit’ between the drawing and the book is demolished: the drawing possesses only three single stitch holes when it should have five pairs of holes making ten in total. Even if it were to be conceded that two inner stitches might once have been present, today’s three single holes should be three pairs of holes, making six holes in total, not three.


When we sent our previous “La Bella Principessa” post with the newly disqualifying physical/technical evidence to the drawing’s owner, Peter Silverman, (13 June), he dismissed the bearers of the information by alleging lack of expertise: “I leave the attribution question to serious and highly qualified experts!!!” In support of his professional slur, Silverman copied-in two messages to us. The first had been sent to him, at his request, by a costume expert, Elisabetta Gnigera. The second Silverman had sent to Jean Penicaut, the CEO of Lumiere Technology. It was evidently written in haste and heat:

“Dear Jean
I am sorry but we, as owners of the BP, are not to be told how and with whom to talk! I understand your frustration in dealing with Artwatch and Franck but i feel that Pisareks statement must not and cannot be left unchallenged! I therefore request you to rebut each and every point in this latest statement-most importantly of all i would like to see the INDISPUTABLE proof of the binding holes, in a first and separate email to me! Unfortunaley Martin has made statements which can be perverted by anyone in bad faith-equivocal statements quoted in the first part of the enclosed article!!
“I would like Elisabetta to comment on the costume questions.
And i would like YOU to extensively quote from the lab results of La Veneria*, which is very helpful to our cause! [*This is a reference the conservation laboratory “La Venaria Reale” which has conducted analysis of the drawing.]
“We cannot afford to lose the high ground’ in this battle-no matter the bad faith of our ennemy.
“To avoid your corresponding with them please send the rebuttal to me. I INSIST THAT THIS IS AN ABSOLUTE NECESSITY!!
Best, peter

“PS-the good news is that there is a very serious party interested in acquiring a share in the BP(highly confidential) and July 1 will be a decisive day!!!”

It would seem after more than a month that Lumiere Technology has not provided the owner with indisputable evidence of a connection between the drawing and the Warsaw book that would counter Pisarek’s account. On 14 June we replied to Mr Silverman:

“Speaking of clarification and your requests, I note the various requests from the ‘owners of the BP’ to your associates
to read our current post, and your talk of a prospective part-sale of the BP. Can I take it that the potential buyer of whom you speak has been similarly advised?

“Also, perhaps you might say how you will respond if Jean Penicaut advises you, as we would predict, that he can find
no ‘INDISPUTABLE proof of the binding holes’ that might enable you – or he on your behalf – ‘to rebut each and every point in this latest statement [in the then current AWUK post]’”?

Concerning the La Venaria Reale laboratory reports, we asked Mr Silverman on 15 June:

“On your technical ‘proofs-of-authenticity’ and our possible viewing of your Swiss-vaulted, soon-to-be part-sold drawing, might we not deal with both by: a) your sending to us all reports and data that have been made available to you; and, b) your bringing the drawing to either Paris or London so that we might arrange a group viewing by sceptics and rejecters?”


After more than a month we have received no technical reports on “La Bella Principessa”. Lumiere Technology’s
apparent silence on the conflicting number of stitch holes seems remiss. In our experience it is valuable to see the reports themselves because evidence can sometimes be interpreted and presented in ways that might mislead. For example, it has been claimed (technically-speaking correctly) that carbon dating has established a 95.4% probability
that “La Bella Principessa” had been made at some point between 1440 and 1650. On that particular technical examination and very wide range of possible ages, Pascal Cotte (2010, p. 110) has claimed a number of things in a single sentence:

“This dating confirms that the portrait could well have been made in Leonardo’s lifetime, supporting Martin Kemp’s proposed date in the mid-1490s and virtually eliminating the possibility that it is a 19th century pastiche.”

This was all quite misleading. A confirmed “could well have” remains a “could have” and does not become a confirming “was”. A “virtually eliminated possibility” remains a possibility. Taken as a whole and properly appraised, the data itself cannot reasonably be said to support Kemp’s claimed date and authorship – in fact, it does the opposite.

Cotte’s claims rest on what is only a loose and very wide overall estimation of probability. While it is true to say there is a 95.4% chance that the sheet appeared at some point between 1440 and 1650, there is not a 95.4% probability that it appeared before the mid-1490s when the Sforziad was made. Even on that loose, overall range of possibilities, it would be more accurate to say that because we know (today) that the Warsaw book was made in the 1490s (and had known in 2010 that the proposed subject of “La Bella Principessa”, Bianca Sforza, had died in 1496), it is three times more likely that the “La Bella Principessa” sheet post-dated rather than predated the book. What has not been acknowledged is that within the overall figure, the probabilities had been greatly more precisely quantified.

It was said in the report, for example, that there was a 68.2% probability that the sheet was made between 1470 and 1650 and that, within this period (see Fig. 4 below), there was only a 27.2% probability that the drawing was made between 1470 and 1530 – and this was compared against the appreciably greater probability (41.0%) that the sheet was made some time between 1550 and 1650 – which would place the sheet altogether much later than Leonardo who died in 1519. Properly read, with a proposed date for the drawing set in the mid-1490s, the data shows that there was only a 13.6% probability that the “La Bella Principessa” sheet existed when the book was made. When the general 95.4% probability of an origin anywhere between 1470 and 1650 and the 13.6% probability of an origin between 1470 and 1495 are expressed as racing odds, it is seven times more likely that the sheet was made after the book than before it. And the odds of seven to one against pertain to the vellum sheet itself, not to the possible dates of execution for the drawing. Even if this sheet had once been present in that book, such a dating would indicate only the age of the material, not the date of the drawing’s execution. On this last, we should recall that Eric Hebborn advised in his The Art Forger’s Handbook that a prime source of old materials for forged drawings is obtained from blank end papers in books. Thieves cut valuable illuminated pages from books. Forgers crave blank pages but will make use of a blank side by gluing its reverse firmly to some impenetrable material.

Above, Fig. 4: The carbon dating report on the “La Bella Principessa” sheet (as published by Kemp/Cotte, 2010, p. 110).


Where Mr Silverman declines to make reports available to us, and Pascal Cotte fails to demonstrate a fit between the drawing’s three stitch holes and the book’s ten stitch holes, we now present further visual proofs and documentary confirmation of the previously claimed mismatch to demonstrate precisely why “La Bella Principessa” could never have been part of the Warsaw Sforziad.


On 23 June 2016 Barbara Dzierzanowska, the Head of Department of Old Prints BN at the National Library of Poland, wrote to Kasia Pisarek:

“Dear Madam,

I would like to inform you that yesterday we entered the Treasury and re-examined the Sforziad, which has confirmed that the binding stitches are double and there are 10 holes.

Yours sincerely,

Barbara Dzierzanowska”


That the stitching of the Sforziad was made through double holes can be seen by eye on the book itself, as shown below at Fig. 5.

Above, Fig. 5: A stitch made through two holes, as seen on the numbered page 1 of the Warsaw Sforziad. In this photograph, the top stitch and the two flanking holes are shown but some of the other holes can also be seen on stitches below it. This stitch/holes configuration would have been evident when (as described above) a full-size facsimile of “La Bella Principessa” was inserted into the Sforziad at precisely this point. This evidence is also available online: our image was taken from the detailed record of the entire book that is carried on this site: Polona – La Sforziada.


When Kasia Pisarek inspected the book for the second time, she asked that the dimensions of the pages and the relative positions of the stitch holes be marked along the edge of a piece of paper. This was done by the library’s books’ conservator in her presence and that of the chief librarian. Intervals between the stitch holes were marked in pencil along the two sides of the strip of paper and these are shown here at Figs. 6 and 7. When we marked off those measurements onto a separate sheet of paper, to prepare the diagram at Fig. 8, and then measured them on our sheet with a ruler, they were all exactly as given by Pisarek. We can be sure, therefore, that the dimensions and ratios between the stitch holes as shown below at Fig. 8 have been accurately established and physically transported to ArtWatch UK – and at practically zero-cost by means of sharp pencils and two pieces of paper.

Above, Figs. 6 (top) and 7: The strip of paper on which the book’s page size and stitch holes were recorded, as described above.

The conservator explained to Pisarek that the present positions of the stitch holes were those of the original construction of the book and that, therefore, there was no possibility that the book had once been bound with only three stitches. She made diagrams on the strip showing (at Fig. 7) different ways of executing stitching with double holes.


1) According to Kemp and Cotte, the dimensions of the vellum pages of the Sforziad vary from 33.0 to 33.4 cm in height, while the drawing is 33 cm high.

2) I have carefully checked the dimensions with the Librarian in March 2016. All the pages are at least 33.4 cm high and more, up to 33.7 cm. The size of 33 cm would be far too small for the book.

3) The 5 holes in the book are in fact all double holes. Each of the 5 holes is two small holes, between which a string passes. The distance between the two small holes is about 3 mm. The double holes were never mentioned by Kemp or Cotte.

4) According to the conservator who was present at the time of my last visit, this is the binding that follows the original binding as there is no damage of any kind. So in total there were as many as 10 small holes, not 3 single ones as in the drawing.

5) I measured the distances between the 3 holes that Kemp and Cotte measured in La Bella Principessa. The measurements were taken from the middle of the double holes.

6) The distance between the bottom hole and the middle hole is 11.35 cm in the Sforziad, while in the drawing it is 11.06 cm.

7) The distance between the middle hole and the top hole is 11.7 cm in the Sforziad, while in the drawing it is 11.44 cm.


Above Fig. 8: We took the dimensions of the Sforziad’s page and stitch holes from the strip of paper marked by the Polish National Library’s books’ conservator (as shown at Figs. 6 and 7) and drew them in black, as above, and marked “WS”. We then drew in red the “La Bella Principessa” sheet (here marked “LBP”) and its stitch holes as given above by Pisarek.
As can be seen above, it is impossible to align the drawing’s single stitch holes with their claimed counterparts in the book. If the drawing’s centre hole is aligned with the centre of the two central holes in the book (as shown on the left here), its other two holes fall short of their claimed counterparts.
If the LBP drawing’s upper hole is aligned with the centre of book’s two upper holes, its central and lower holes fall progressively further short of their claimed counterparts on the book.
In short, there is no fit or match between the book and the drawing – and which drawing in all probability post-dated the book, for reasons indicated above.

Those who would continue to give this drawing to Leonardo must now find some other means of filling a five centuries absence of provenance and of squaring intractable technical circles. We will examine next the supposed left-handed execution of “La Bella Principessa”.

Michael Daley, 21 July 2016

Problems with “La Bella Principessa” – Part III: Dr. Pisarek responds to Prof. Kemp

In June 2015 Kasia Pisarek, an independent scholar (and a member of ArtWatch UK) published an article, “La Bella Principessa – Arguments against the Attribution to Leonardo”, in the Polish scholarly journal Artibus et Historiae.

In her article Dr Pisarek presented a number of interlocking historical, aesthetic and technical criticisms of the attribution to Leonardo of the drawing “La Bella Principessa”, as it has been made and advanced by Professor Martin Kemp. In response, Prof. Kemp produced an article (“Leonardo da Vinci La Bella Principessa: Errors, Misconceptions, and Allegations of Forgery”) which challenges Dr Pisarek’s account on grounds of what he claims and alleges to be: “mistakes, misconceptions and a series of false allegations”.


In his response Kemp says “I do not run an authentication service, but research items of special interest regardless of ownership.” More recently ( May 16) Kemp announced on his website that “After speaking at the Art in Authentication Congress in The Hague, I confirm that I am withdrawing the [unpaid – Ed.] ‘advice service’ I have been providing.”


Kemp discloses that in responding to Pisarek’s article he also sought by “extension” to counter other un-identified challenges to his Leonardo attribution. When this multi-targeted professional defence was submitted to Artibus et Historiae, it was rejected, as Kemp acknowledges, and as the Art Newspaper reports (“La Bella Principessa: Still an Enigma”, Features, May 2016), because of its resemblance to “an errata list”. The article was subsequently carried on the Authentication in Art website to accompany a paper given by Kemp at the AiA’s May 2016 Congress. This non-profit organisation, on which Kemp serves as an advisor, was founded in 2012 at The Hague. On May 8th we made a formal request to the AiA for Kasia Pisarek’s Artibus et Historiae article also to be posted so that the congress speakers and attendees might see both of what Dr Pisarek’s compilation of evidence consisted and of what Prof. Kemp complained. We have yet to receive a reply. For Kasia Pisarek’s Artibus et Historiae article, “La Bella Principessa – Arguments against the Attribution to Leonardo” click here. For Martin Kemp’s response to it, see: “Leonardo da Vinci La Bella Principessa: Errors, Misconceptions, and Allegations of Forgery”.


In December 2015 Kasia Pisarek delivered a paper based on her Artibus essay at the ArtWatch UK/LSE Law Department/Center for Art Law conference “Art, Law and Crises of Connoisseurship”. At this conference, an arts journalist, Simon Hewitt, delivered an attack from the floor on her article. He did so as a proxy for Kemp, by whom he had been briefed, and for the collector/dealer owner of “La Bella Principessa”, Peter Silverman, with whom he is co-writing a book on what Silverman describes to us as “various aspects of the art market, sometimes highlighted by others’ and my own discoveries”. A research assistant of Kemp’s, Kasia Wozniak, who had spent four years attempting to show that “La Bella Principessa” had once been part of a late 15th century book known as the Warsaw Sforziad, had also written to us in denigration of Pisarek’s article which we had forwarded to her at her request.

Earlier, both Professor Kemp, who had declined an invitation to speak at this conference, and Mr Silverman, had suggested that we invite Hewitt to speak at the conference. Silverman expressly requested that this be done so that Hewitt might “present his discoveries as a counterweight to Ms. Pisarek”. We carry Pisarek’s full reply to Kemp’s listed objections below but comment first on a crucial new aspect of this disputed attribution that has emerged in Kemp’s response to Pisarek.


Above, Fig. 1: A facsimile of the “La Bella Principessa” drawing being inserted into the Warsaw Sforziad (but showing only the relationship of the top of the facsimile to the top of the book and not the accompanying relationship of the facsimile and book at the bottom). Photo by courtesy of Lumiere Technology.

For many reasons, it is essential to Prof. Kemp’s Leonardo ascription that it be accepted that “La Bella Principessa” had originally been incorporated within the Warsaw Sforziad now held in the National Library, Poland. It has not been so accepted because, contrary to press releases claims and media coverage thereafter, nothing material or documentary has established such a relationship. No record of any connection between the drawing and the book has been found despite extensive searches by researchers such as Kasia Wozniak. Moreover, despite extensive searches of Berenson’s archives by Kemp and Silverman, no record of the supposed 15th century drawing in any context predates its only-recently acknowledged ownership by the late painter/restorer Giannino Marchig. This pictorially and graphically mongrel work remains without a history and, prior to September 2011, without any claim – even by its only known previous owner – that it might have been a work by Leonardo da Vinci.

Martin Kemp has challenged Kasia Pisarek’s measurements between the stitches in the book’s binding. He and Pascal Cotte (of Lumiere Technology) claim that three stitch holes are present on the left hand edge of the “La Bella Principessa” sheet and that these match three of the book’s five stitches. No confirming visual evidence has been produced in support of this claim. In addition to fresh evidence on dimensions provided below by Pisarek, it might be noted that the Kemp/Cotte claims of a match have been variously and only rarely unequivocally phrased. All emphases below are added:

The stitch holes in the vellum of the portrait match those in the book – “The Original Source of the New Leonardo Portrait Discovered”, a Martin Kemp press release, 27 September 2011.

“Three of the stitch marks, the ones that we can still see on the edge of the ‘Bella Principessa’, match as well as they conceivably could – Martin Kemp, Artinfo interview, “The Da Vinci Detective: Art Historian Martin Kemp on Rediscovering Leonardo’s Tragic Portrait of a Renaissance Princess”, by Andrew M. Goldstein, 11 October 2011;

“During our studies at the National Library, we inserted a facsimile of the portrait into the relevant opening of the book where the size matched very closely – Martin Kemp, item 14, “Leonardo da Vinci La Bella Principessa: Errors, Misconceptions, and Allegations of Forgery”, on the Authentication in Art website. See Fig.1, above;

“The current stitching of the volume involves five holes, whereas there are only three holes now visible along the left margin of the ‘La Bella Principessa’. However, these three holes correspond very closely to the corresponding ones in the book.” – Martin Kemp and Pascal Cotte, “La Bella Principessa and the Warsaw Sforziad”, Lumiere Technology website, September 2011.


With linear measurements a near-miss is as good as a mile. If a hole is two millimetres adrift of a stitch there is no match. Claiming “correspondences” and “close” matches between the three holes and the five stitches is problematic enough, but, as Kasia Pisarek has now re-confirmed, the three holes in the “La Bella Principessa” drawing do not correspond with three of the book’s five stitches. Moreover, Kemp’s imprecision came with a perplexing multiple caveat: “In measuring the distances between the holes and matching these distances in the book and the portrait we allowed for four potential sources of error” – Kemp/Cotte, item 13, “La Bella Principessa and the Warsaw Sforziad”, Lumiere Technology website.

If incorporating an allowance for one potential source of error would necessarily be weakening to the force of a claimed match, how might allowances have been made for four different sources of error? How were the different “potentials-for-error” calibrated and weighted one against the three others? With accounts of this attribution, too many features remain in flux. For example, explanations offered for the disparity between the drawing’s three stitch holes and the book’s five stitches have shifted. In 2011 Kemp/Cotte wrote:

“The second task was to see if the holes in the portrait and the stitching pattern in the book corresponds. There is an obvious difference. The current stitching of the volume involves five holes, whereas there are only three holes now visible along the left margin of “La Bella Principessa”. However, these three holes correspond very closely to the corresponding ones in the book…The different number of stitching holes may result from the untidy way the left margin of the portrait has been cut, or from two intermediate stitches being added when the book was later rebound in standard Zamoysky livery. The former explanation is more likely.” (Emphases added.)

The suggestion that the book might possibly have been bound originally with only three stitches seems to have been abandoned altogether. Martin Kemp now accepts in his response to Kasia Pisarek that the book always had five stitches but claims as a countering fact against this recognition that: “The irregularity and extensive damage along the left margin explains why two of the five stitch holes are no longer clearly discernible.”


The posited stitch holes cannot be said to be “no longer discernible” because there is no evidence that they were ever present. Prof. Kemp here begs a question on which this attribution turns. The roughly cut edge cannot be taken to have explained these absences. What Kemp offers, in truth, is (an implausible) hypothesis that ignores the technical exigencies of book binding and the dimensional realities of the “La Bella Principessa” sheet. When books are being made, the stitches are inserted along the line of a fold made collectively to the small number of sheets that form one of the book’s sections or “quires”. In the case of the Warsaw Sforziad, Pascal Cotte established (by taking and combining 70 precisely-focussed macro-photographs) that each quire was composed of four sheets (folios) which, when folded and stitched, comprised sixteen numbered pages. The book binder’s craft requires that the stitching occurs precisely along the crease line of the folded sheets. This careful alignment is necessary if the pages are not to cockle and for the book to open easily.

The three holes on “La Bella Principessa” have been taken to relate (- more or less, but never exactly) to the book’s central and two outer stitches. Had the “La Bella Principessa” sheet been incorporated in the Warsaw Sforziad when it was made in the late 1490s, the two inner stitch holes would be expected to be present on the sheet, even as it is today, and notwithstanding its roughly cut left-hand edge.

At Fig. 2 below, we see the white arrows and circles with which Pascal Cotte identified what are said to be “La Bella Principessa’s” three stitch holes. On the image on the left, we have drawn in red the alignment of the present three holes and have indicated with arrows where the two hypothesized additional stitching holes would be expected to be located. Both holes would fall within the present sheet despite its roughly cut left-hand edge. In the image on the right of Fig. 2 we again indicate (in black) the alignment of the present three holes, but show in red how the alignment would be disrupted had the two hypothesized additional stitch holes been situated to the left of the present sheet, as Prof. Kemp now claims in “explanation” for their absence from the sheet itself. Such a positioning would have resulted in a zigzag, not a row, of stitch holes. It is impossible to envisage how four sheets of vellum might have been folded so as to produce a neatly zigzagging crease.

Aside from the above problem, any lingering hope that this “La Bella Principessa” sheet might once have formed part of the Warsaw Sforziad will have to be abandoned in the light of Kasia Pisarek’s latest findings described below on her second examination of the Warsaw Sforziad.

Above, Figs. 2 and 3. In Fig. 2 (top) we see, in the left and right images, the white arrows and circles with which Pascal Cotte located the “three holes showing that the image was once part of a codex or manuscript”. Given that the book (the Warsaw Sforziad) from which this sheet is said to have been cut was originally bound with five stitches, had the “La Bella Principessa” sheet once formed part of that book, it would today have five stitch holes, not the present three. In Figs. 2 and 3, we indicate with arrows (in red and then in black) where the missing two stitch holes would, for the reasons given above, be expected to have been located.


When Andrew Goldstein asked Martin Kemp in an Artinfo interview in October 2011 what, on seeing the drawing, had convinced him it might be a Leonardo, he replied:

“So the initial connoisseur’s reaction merely tells you that something is worth looking at, but at any point one wrong thing can throw that all away — a later pigment, a bit of something that might come up about its history to indicate it was forged at some point, and so on. I was trained as a scientist, and if you have a scientific theory, you only need have one bit of the experiment that says, ‘this is not right,’ and the whole thing collapses. You always have to be looking for that one thing that is going to demolish the whole expectation that’s being set up.”

Kemp has given other grounds for caution when making attributions. On first encountering “La Bella Principessa”, he told Silverman, “I immediately saw it was in a different league from the others. But I was still very, very cautious. I didn’t want to jump at it because once you start believing you can summon up all the evidence you need.” (Peter Silverman, Leonardo’s Lost Princess: One Man’s Quest to Authenticate an Unknown Portrait by Leonardo da Vinci, 2012, p. 74.) Kemp had become a believer in the Leonardo attribution by 28 September 2011 when he issued a press release “The Original Source of the New Leonardo Portrait Discovered”. He added, “This (press release attached without the pics) should more or less settle the arguments – though probably not knowing the myopia of the art world.”

In 2011, after Kemp and Cotte had inserted their facsimile “La Bella Principessa” into the book, Kemp expressed himself 80 per cent confident of the drawing’s Leonardo attribution in a National Geographic film of the occasion. However, this was not the first time that a claimed “fit” between the facsimile and the book had been made and filmed by National Geographic. Peter Silverman describes in his book how, in December 2010, he had established a match in a different part of the book:

“We began by measuring the page size to see if it corresponded to “La Bella Principessa” and were gratified to see that it did, within a millimeter or two (a minute fraction of an inch)… Martin [Kemp] had surmised that the drawing would have been placed either at the very beginning or the very end of the book, but after careful examination we could find no trace of a cut page in either place. ‘May we turn each page?’ I asked. It was not a simple request. The book was nearly two hundred pages, and it would be a bit laborious for her [Anna Zawisza, the head of manuscripts] since utmost care had to be used so as not to damage the precious work in any way…It was apparent that the three pinholes where the binding had been sewn, noted earlier by Martin, which we had hoped would be a key to matching, would not be relevant, since the book had been rebound using five sutures…We slowly continued to turn each page, but there was no sign of a missing page…I had begun to abandon hope and to mentally prepare myself to return empty-handed. But then Zawisza turned page 161. There was a momentary beat of silence, and then she and I let out muffled cries. There, before our incredulous eyes, was what seemed to be the missing link, the element we longed to find: a remnant of a cut and extracted page of vellum that was the same darkish yellow as “La Bella Principessa”. We could barely contain our emotions. We measured the undulation of the remnant, and it corresponded exactly. Kathy [Silverman’s wife] and Kasia [Wozniak, art historian] came round to see for themselves, while David [Murdoch, National Geographic producer] filmed the historic moment. Even the armed guard was caught up in the excitement. Zawisza, who had carefully studied the book on past occasions, murmured how unhappy she was that she’d never noticed the missing page, now so glaringly obvious from the protruding remnant…”

That filmed historic moment was eclipsed by the moment in which Kemp and Cotte discovered a (preferred) location for the drawing at the front of the book. On her second examination of the Warsaw Sforziad, Dr Pisarek has learned that each of the five stitches in the book’s binding resulted in two holes, through which a string was passed. Thus, now that it is accepted that the book was originally bound with five stitches, each of which generated two holes, and that the “La Bella Principessa” sheet possesses only three of the necessary ten holes – and three where there should be six – there is no physical match between the drawing and the book, just as there is no documentary record of a Leonardo drawing having been bound within the book. Those who continue to see the hand of Leonardo in the drawing itself must now find an alternative history and another princess to accompany and bolster it.

Michael Daley 24 May 2016

Kasia Pisarek: A reply to Martin Kemp’s essay “Leonardo da Vinci La Bella Principessa. Errors, Misconceptions and Allegations of Forgery”

Professor Kemp has written an essay in response to my article “La Bella Principessa; Arguments against the Attribution to Leonardo”, Artibus et Historiae, No. 71, XXXVI, June 2015, pp. 61– 89.

In his essay, Prof. Kemp lists what he deems a series of errors and misconceptions in the Artibus article, but says he does not wish to address the issues of attribution I raised.

The purpose of his article is, however, an attempt to counter or undermine my findings.

I will answer his points in the order and with the numbered headings used by Kemp in his text.

[Martin Kemp] “1) Bibliographical”

[Kasia Pisarek] Martin Kemp says that most of my material is quoted from the internet and that I make only one reference to his book in my footnote 50.

This is incorrect. I make extensive reference to his book on the opening page and further references in footnotes 54, 57, 59 and 64. I have examined it as thoroughly as would be expected of any researcher. I also referred to many other books and articles which were accessed from libraries and not from the internet. These were:

M. Kemp and P. Cotte, The Story of the New Masterpiece by Leonardo da Vinci: La Bella Principessa, London, 2010; M. Kemp, Leonardo (rev. ed.), Oxford, 2004; P. Silverman, Leonardo’s Lost Princess: One Man’s Quest to Authenticate an Unknown Portrait by Leonardo Da Vinci, New Jersey, 2012; C. Geddo, ‘A “Pastel” by Leonardo da Vinci: His Newly Discovered Portrait of a Young Woman in Profile’, Artes, 2008–2009, pp. 67–87; C. C. Bambach, ‘Leonardo’s Notes on Pastel Drawing’, Mitteilungen des Kunsthistorischen Institutes in Florenz, vol. 52, 2008, no. 2/3 (Le tecniche del disegno rinascimentale: dai materiali allo stile. Atti del convegno internazionale, Firenze, 22–23 settembre 2008, ed. By M. Faietti, L. Melli, A. Nova), pp. 177–204; M. Gregori, ‘A Note on Leonardo’, Paragone, LXI, 2009, no. 723, pp. 3–4; D. Ekserdjian, ‘Leonardo da Vinci: “La Bella Principessa” – The Profile Portrait of a Milanese Woman’ (book review), Burlington Magazine, vol. 152, 2010, no. 1287, June (Attributions, copies, fakes), pp. 420–421; P. C. Marani, ‘Deux nouveaux Léonard?’, Dossier de l’art, 2012, no. 195, avril, pp. 58–63. Giannino Marchig, 1897–1983: paintings and drawings, exh. cat. London, 1988; Giannino Marchig, 1897–1983, exh. cat., Geneva, 1985; Giannino Marchig: 1897–1983: dipinti, disegni, incisioni, exh. cat. Florence, Gabinetto disegni e stampe degli Uffizi, 12 March – 5 June 1994 (Italian ed.); J. Cartwright (Mrs Henry Ady), Beatrice d’Este, Duchess of Milan, 1475–1497. A Study of the Renaissance, London, 1910; B. Horodyski, ‘Miniaturzysta Sforzów’, Biuletyn Historii Sztuki, 16, 1954, pp. 195–213; E. McGrath, ‘Ludovico il Moro and His Moors’, Journal of the Warburg and Courtauld Institutes, vol. 65, 2002, pp. 67–94; L. Syson with L. Keith, Leonardo da Vinci, Painter at the Court of Milan, exh. cat. National Gallery, London, 2011; Dizionario delle origini, invenzioni e scoperte nelle arti, nelle scienze…, Milan, 1831; B. Berenson, The Drawings of the Florentine Painters, vol. III, Chicago, 1938; Leonardo da Vinci, Master Draftsman, ed. by C. C. Bambach, exh. cat., The Metropolitan Museum of Art, New York, 2003; Z. Zygulski Jr, ‘Ze studiów nad Dama z gronostajem. Styl ubioru i wezly Leonarda’, in: Swiatla Stambulu, Warsaw, 1999 (first published in Biuletyn Historii Sztuki, vol. 31, 1969, no. 1, pp. 3–40).

The 2012 Italian version of Kemp/Cotte’s 2010 book is a translation from the English with the addition of the Sforziad hypothesis. The latter had already been published on the Lumiere Technology website and I discussed it at length.

Gnignera’s text was in Italian so I used Prof. Zygulski’s extensive knowledge of historic costume in general and coazzone in particular. The Monza catalogue (2015) was not published when I submitted my paper. The 2014 exhibition catalogue from the Galleria Nazionale in Urbino was also unavailable. To my knowledge these later publications have not yielded any conclusive evidence.

Prof. Kemp said that I have not addressed any of ‘the scientific evidence in the two books related to the lower layers of the image, the pentimenti or the condition and retouching in various media’ and goes on to say ‘contrary to Pisarek’s assertions, the interventions of restorers are documented in both books’. The latter sentence must refer to my ‘it is also strange that he did not consider that the drawing might have been retouched and repainted at a later time’ (p.79). Prof. Kemp has taken this out of context. I said that he did not mention the restorations in that particular passage of his book Leonardo (p. 210).

I not only analysed his art historical arguments in my text, but also the technical evidence presented by Cotte – which is to say:

– The trois crayons, pen and ink and bodycolour technique on vellum (unprecedented for Leonardo);

– The X-rays (inconclusive, in Cotte’s own words “did not yield significant new findings”, p. 154)

– The Carbon-14 dating of the vellum (wide-ranging 1440-1650, not constituting proof in itself as anyone could draw at any time on a blank folio removed from a manuscript)

– The quality of the vellum (rough; drawing on the hair-side; does not match the Sforziad’s smooth and well-prepared support; Birago’s illumination on the skin-side)

– The left-hand hatching (dry, timid and mechanical; on the outside of the contour of the profile, unlike in all Leonardo’s female portraits)

– The presence of three stitch holes (the Warsaw National Library Sforziad has five holes)

– The ‘knife marks’ when the folio was cut off (unnecessary, if the folio has been removed during rebinding).

– The retouchings of a later restorer (Marchig’s)

– The fingerprint evidence (no longer valid)

– The pentimenti, in the same place as in Leonardo’s Windsor portrait (a negative point, as La Bella Principessa could be based on that drawing).

At this point I would like to discuss some more scientific evidence:

On page 109:

“The support is probably the fine-grained skin of a calf”.
To the contrary, the images show an irregular grainy surface with visible follicles. Both Geddo and Turner described the support as “rough animal hide” and the surface of the vellum as being “pitted”.

“The portrait was drawn on the smooth ‘hair’ side”.
To the contrary, the hair-side has follicles so it is the rough side, not the smooth side.

Contrary to Prof. Kemp’s claim that I ignored Geddo’s contributions, I quoted her (p. 76), and she said exactly the opposite: “Besides the presence of the follicles, the rough unworked surface of the hide and its darkened, somewhat yellowish colour show that the portrait was made on the outer surface of the skin (formerly fur­covered) and not on the inner one covering the flesh, which was aesthetically the superior of the two and commonly used as a support for written documents”.

I quoted extensively from Geddo’s article “A ‘Pastel’ by Leonardo da Vinci: His Newly Discovered Portrait of a Young Woman in Profile”, in Artes, 2008–2009, pp. 67–87, on my pages 62, 76 and 88.

On page 114:

The discovered “small area of pen marks along the left edge of the support” described by Cotte as Leonardo’s “pen trials”. This would surely have no place in a drawing destined for a luxury book presented as a gift to the Sforzas.

On page 154:

A problem with the X-rays:

‘Because white chalk (calcite or calcium carbonate) does not absorb X-rays to any great extent, the luminous zones of the sitter’s face ought to have appeared grey in the X-ray. On the contrary, however, they appear very white here, indicating the presence of a significant amount of dense material in the chalks area – which seems to contradict all the physical evidence considered so far.’

Cotte attributes this anomaly to the technician supposedly over-exposing the plate. This confirms his own observation that X-rays “are vulnerable to diverse interpretation”.


[KP] I did not say that the Marchigs were involved in forgery of any description. What I did say was that Giannino was familiar with Leonardo’s technique as a restorer and a “Leonardesque painter”. He was able to make such a drawing if he had wanted to, but clearly he had not tried to sell La Bella Principessa as a work by Leonardo.

Prof. Kemp does not explain, however, why the drawing had no provenance prior to Marchig’s ownership, and, as Michael Daley has recently pointed out, Professor Kemp and the drawing’s owner, Peter Silverman jointly trawled Berenson’s archive in hope of finding some pre-Marchig record but found none.

[MK] “3) The assertion that there is an ‘almost total absence of close comparisons with unimpeachable works by Leonardo.’”

[KP] The offending phrase above was written not by me but by David Ekserdjian in “Leonardo da Vinci: ‘La Bella Principessa’ – The Profile Portrait of a Milanese Woman”, The Burlington Magazine, vol. 152, 2010, no. 1287, June (Attributions, copies, fakes), pp. 420–421.

I used the same Leonardo comparisons as Prof. Kemp, but where he saw striking similarities, I saw possible imitation.

As to Cecilia Gallerani, although the structure of the eye looks comparable, it is round, soft and alive in Leonardo’s portrait, and dry, linear and lifeless in La Bella Principessa. The iris is drawn as a flat disc and the eyelid is marked with clear cut lines, unlike in nature.

Cotte states on p. 177: “Leonardo, for example, consistently made the bottom of the eye’s iris coincide exactly with the edge of the lower eyelid”.
This is not always the case. In Portrait of a Woman in Windsor or in La Belle Ferroniere the iris does not touch the lower eyelid, while in some works by Leonardo’s followers it does.

[MK] “4) The lack of records of Leonardo making the drawing”

[KP] Prof. Kemp wrote that all Leonardo’s known works are “unrecorded in his writings”. Leonardo does in fact mention two Madonnas in a sheet of sketches (Gabinetto Disegni e Stampe degi Uffizi, Florence, 446 E) inscribed: “…1478, I began the two Virgin Marys”, possibly referring to the Benois Madonna in St. Petersburg. He also mentions in a note his sculpture of the Sforza Horse (Ms. C, fol. 15v; R 720; B 44; V 53). And in an undated letter (about 1491-95), he writes together with De Predis about being underpaid for the Virgin of the Rocks.

The 16th century record in the Zamoyski collections Kemp refers to applies only to the Sforziad, not to the drawing, which was unrecorded there.

[MK] “5) ‘The entirely unusual for Leonardo medium of vellum commonly found in manuscripts led Prof. Kemp and his colleagues, including David Wright, Emeritus Professor of Art History at the University of South Florida, to search fifteenth-century codices for an excised illumination.’”

[KP] Prof. Kemp writes that “the author’s narrative of an extensive search is imaginary.”

But Dalya Alberge wrote in her article, “Is this portrait a lost Leonardo?” in The Guardian, on 27 September 2011:

“Earlier this year, he [Prof. Kemp] embarked on what he describes as a ‘needle-in-a-haystack’ search for a 15th-century volume with a missing sheet. […] Against the odds, Kemp tracked the volume down, to Poland’s National Library in Warsaw.”

[MK] “6) Forging a Leonardo?”

[KP] To be clear, I only said that the drawing could be a compilation of Leonardo’s works and other sources such as a bust by Cristoforo Romano.

[MK] “7) Pisarek’s reliance on Julia Cartwright”

Cartwright’s work is the only one specifically on Bianca Giovanna Sforza I could find in the English language. As there are no other secure portraits of Bianca Giovanna, the Principessa hypothesis is not supported by any evidence either.

Cartwright’s identification of The Musician as the portrait of Galeazzo Sanseverino, Bianca’s husband, looks convincing. The companion portrait in the Ambrosiana could then be showing his wife Bianca, but she looks very different to La Bella Principessa. Also Professor Carlo Pedretti in his Leonardo: The Portrait, 1999, called the Ambrosiana portrait (p. 23) “a probable portrait of Bianca Giovanna, the illegitimate daughter of Francesco Sforza.”

[MK] “8) Bianca Maria Sforza and earlier scholarship”

Even if the identification and dating of the portrait ‘pre-dates the research into the Sforziad’, as stated by Prof. Kemp, there is still the problem of the dating and the too ‘archaic’ style of the drawing.

Kemp does not explain why Vezzosi and Turner identified La Bella Principessa as Bianca Maria Sforza, even if she looks so different to her other known likenesses.

[MK] “9) Cutting out the portrait from the Sforziad in Warsaw”

[KP] There is no evidence that the folio was in the Sforziad and was removed during rebinding. But if it were so, there would be no need to cut out the folio, only to remove it as a complete sheet. A complete sheet (two folios) is indeed missing in the book, which would eliminate the need for excision.

If the folio had been removed during rebinding for its beauty or high value by the Zamoyskis, it would have been recorded in their collections, but there are no such records. Kasia Wozniak’s research has not found any evidence to this effect.

Her hypothesis that the drawing went to the Czartoryski collections in Pulawy where it was identified as by Leonardo is also so far unsubstantiated. There were no such records in the Czartoryski collections. The late Director of the Czartoryski Museum, Prof. Zygulski Jn. never mentioned the existence of a Leonardo drawing in their collections.

The Bona Sforza drawing listed in the 1815 inventory of the Temple of Sybil in Pulawy and mentioned by Wozniak as the possibly misidentified Bianca Giovanna Sforza, refers to a miniature watercolour on vellum illustrated in D. Dec and J. Walek’s, Czasy! Ludzie! Ich dziela. Teatr obrazów ksieznej Izabeli, listed as no. 99. ‘Polish, 16th century’.

There is no connection between my article in Artibus and the interests of the National Library in Warsaw.

[MK] “10) The foliation and inserted paper pages”

[KP] Prof. Kemp himself used the word ‘codex’ to describe the Sforziad in his book Leonardo: Revised edition, 2011, p. 256:
“this tender and refined formal portrait in ink and coloured chalks on vellum has been cut from a codex (a book), namely the copy of the Sforziada in Warsaw produced for Galeazzo Sanseverino.”

The three folios missing in the Warsaw Sforziad were originally left blank as in the other copies of the book in Paris or London.

Geddo described the drawing’s “apparent crudeness in the preparation of the parchment” and “the rough unworked surface of the hide” (A Pastel by Leonardo da Vinci… reprinted in P. Silverman, Leonardo’s Lost Princess, pp. 219-220). This is not true of the Sforziad’s parchment.

I have seen the Sforziad on two occasions. Once in the summer 2012 and more recently in March 2016; the parchment is finely grained and of high quality, as expected in a luxury book for the Sforzas.

My illustrations Fig. 7, 10 and 11 indeed show paper pages. Because they look so similar it is easy to mistake the paper pages for the vellum ones. My Fig. 6 and Fig. 8 are vellum and they look very similar in colour and texture.

Kemp states that I inaccurately said that his “reconstruction of the insertion of the drawing in the Warsaw Sforziad looks unrealistic, as it is facing a printed page”. He wrote that “The reconstruction shows that the portrait would have faced a blank page”. This is incorrect. His “Fig. 12 – ‘Hypothetical Reconstruction of La Bella Principessa as folio 6r” in the online article “La Bella Principessa and the Warsaw Sforziad” does face a printed page.

[MK] “11) Iconography”

[KP] According to Kemp, Horodyski’s pioneering research on the Sforziad I support ‘has been superseded in the light of more detailed knowledge of Sforza court iconography and analyses by later scholars, including Wright’.

Horodyski suggested Gian Galeazzo Sforza and his offspring, such as Bona Sforza, the later owner of the book in Warsaw as the recipient of the Sforziad.

But according to D.R.E. Wright in his article on the Lumiere Technology website (which has now been removed), M. L. Evans and E. McGrath, the Warsaw Sforziad was destined for Galeazzo Sanseverino, Bianca’s husband.

So why is Galeazzo Severino’s profile absent on the Warsaw frontispiece by Birago, where Ludovico’s is in London and Gian Galeazzo’s in Paris, the recipients of the other Sforziads?

Moreover, Galeazzo Sanseverino was not part of the Sforza dynasty and Bianca was illegitimate. All the copies of the Sforziad on vellum were dedicated to members of the Sforza family.

Horodyski’s reading of the symbolic content of the Birago frontispiece more logically pointed to the death of Gian Galeazzo: the lack of the recipient’s profile as emblem, the missing figure of Gian Galeazzo in the boat with Ludovico il Moro, the tears in the handkerchief, the sarcophagus, the broken shield with the initials GZ, the crest with one half with arms of Milan and the other of Aragon for Gian Galeazzo.

After my defence of Horodyski’s interpretation, an Italian scholar Carla Glori published online her very detailed new iconographic study of the illumination: ‘The Illumination by Birago in the Sforziad incunabulum in Warsaw: in defence of Horodyski’s thesis and a new hypothesis’. I am quoting her extensively below.

She said: “The incunabula with the illuminations now in London and Florence were the property of Ludovico il Moro, given the recurrence of the central upper figure of a moor, and the presence of the ensign of the Duke of Bari with his devices called “la scopetta” (the little broom) and “I due fanali” (the two beacons). The Paris and Warsaw incunabula were the property of Duke Gian Galeazzo Sforza and his family, because they are reproducing the devices of Gian Galeazzo himself and of his father, Galeazzo Maria.”

The sieve, which was said to be the emblem of Galeazzo Sanseverino, was Gian Galeazzo’s personal device (created by his father) called “il buratto” (a sieve held by two hands) with the motto TAL A TI QUAL A MI, as illustrated by the “Cassone dei tre Duchi”, Sforza Castle, Milan, 1479-1494.
Glori also added that the sieve device (“il buratto”) is duplicated in symmetrical position in the central area of the Warsaw illumination.
She concluded that “the Warsaw illumination was dedicated to the memory of the deceased Gian Galeazzo Sforza and his family, and that it was certainly dated after his death (1494)”.

Her argument against the Sanseverino coat of arms or imprese supposedly identified in the Birago’s illumination includes:

– The missing Aragonese “A” in the device of the “three intertwined rings with diamonds” appearing on the Warsaw illumination
– The missing Sanseverino NOSTRO È IL MESTIERE motto
– The fact that the hybrid coat of arms of the Warsaw illumination does not correspond to the coat of arms of the Sanseverino dynasty; it should be silver/white not gold/yellow. “Every armorial certifies that the field (“campo”) of the Sanseverino coat of arms was “SILVER” (white), while the field (“campo”) of the coat of arms in the illumination of Warsaw is “GOLD” (yellow)”. “According to Horodyski’s logical and symbolical interpretation, the emblem is an artistic fusion of the traditional emblem of the city of Milan with the yellow and red lines of the Aragona coat of arms.”
– The reference of the initials “GZ” (appearing in the ducal documents and iconography, also on the ‘Cassone dei Tre Duchi’) to the memory of the deceased dukes Galeazzo Maria and Gian Galeazzo, not Galeazzo Sanseverino.
– The absence of any reference to Galeazzo Sanseverino and his biography such as the tournament lance of the famous jouster, while the ducal arms on the “Cassone dei Tre Duchi” are present: the round shield, the quiver with arrows and the sword. The depicted starry armour on the left is not the typical armour of a jouster. It is empty as Gian Galeazzo is dead, and it is almost identical to the one worn by him in the Paris illumination.
– The presence of a body of heraldic devices celebrating the Visconti-Sforza dynasty and referable in particular to Galeazzo Maria Sforza and his son Gian Galeazzo such as the greyhound/the tree/the divine hand (Francesco Sforza); the “capitergium” device (a bandage with a knot) dedicated to Gian Galeazzo Visconti, the first Duke of Milan, celebrating the Visconti dynasty; the rising waves (“onde montanti”); the three intertwined rings with diamonds (“i tre anelli intrecciati con diamante), by Muzio Attendolo, the founder of the Sforza dynasty: it was probably given to him in 1409 by the Marquis of Ferrara Niccolò II d’Este after the conquest of Reggio Emilia. They are not emblems of Bianca Giovanna as was advanced, but of members of the Sforza family in general.

According to Glori, “we have no evidence that the incunabulum now in Warsaw was confiscated in Milan during the French invasion. In 1517 Antonio de Beatis saw some precious incunabula in the Royal Library of Blois, but he did not cite the Sforziad as being amongst them in his autograph manuscript XF28 of the National Library in Naples. It is plausible that the incunabulum now in Warsaw was a wedding gift to Bona Sforza from her mother Isabella; I propose also the hypothesis that she received the gift from her aunt Caterina Sforza, probably when she left Milan with Isabella after the downfall of Ludovico il Moro.”

[MK] “12) Betrothal and Marriage”

[KP] Although the word ‘betrothal’ might have been more appropriate than ‘marriage’ in the case of Bianca Sforza, others also wrote that her ‘wedding’ (or nuptials) took place in 1490 or late 1489.

Julia Cartwright in her Italian Gardens of the Renaissance and Other Studies, 1914, (reprint 2013) wrote p. 174: “On the 10th of January, 1490, the wedding [of Bianca and Galeazzo] was solemnised in due splendour in the Castello of Milan (…)”.

Edward McCurdy in The Mind of Leonardo da Vinci, New York, 2013, wrote “Bianca Sforza, a natural daughter of Ludovic who in 1489, while still a child, was married to the famous captain Galeazzo di Sanseverino.” p. 301.

Wikipedia entry for Galeazzo Sanseverino also says “He was married to Bianca, illegitimate daughter of Ludovico Sforza, in 1489.”

[MK] “13) The Technique”

[KP] It was Prof. Kemp himself who said that Leonardo never worked on vellum in his book The story of the new masterpiece… p. 35: “There are no other known works by Leonardo on vellum, but there is previously neglected evidence of his interest in making coloured images on prepared animal skin.”

Turner also wrote in his online Statement concerning the portrait on vellum by Leonardo, p.3: ‘Also apparently unprecedented [for Leonardo] is the use of vellum or parchment as a support for the new portrait.’

Geddo also wrote: “The use of parchment was until now unknown in the work of Leonardo (…)”, in P. Silverman, Leonardo’s… p. 226.

In reference to Jean Perréal and dry colouring, the quotation in full is as follows: “Piglia da Gian de Paris il modo di colorire a secco e’l modo del sale bianco e del fare le carte impastate, sole e in molti doppi, e la sua casetta de’colori”.

The translation for carte impastate as ‘paste-board’ is not anachronistic, as it was used as early as 1760 in Joseph Baretti’s, A dictionary of the English and Italian languages, Vol. 1: “Cartone [composto di piu carte impastate insieme] paste-board.”

I have only inspected the vellum of the Sforziad in Warsaw, not the vellum of the drawing, but both Geddo and Turner have described it as ‘rough animal hide’. This is most certainly not what you will find in the Sforziad in Warsaw.

[MK] “14) Dimensions”

[KP] According to Kemp and Cotte, the dimensions of the vellum pages of the Sforziad vary from 33.0 to 33.4 cm in height, while the drawing is 33 cm high.

I have carefully checked the dimensions with the Librarian in March 2016. All the pages are at least 33.4 cm high and more, up to 33.7 cm. The size of 33 cm would be far too small for the book.

The 5 holes in the book are in fact all double holes. Each of the 5 holes is two small holes, between which a string passes. The distance between the two small holes is about 3 mm. The double holes were never mentioned by Kemp or Cotte.

According to the conservator who was present at the time of my last visit, this is the binding that follows the original binding as there is no damage of any kind. So in total there were as many as 10 small holes, not 3 single ones as in the drawing.

I measured the distances between the 3 holes that Kemp and Cotte measured in La Bella Principessa. The measurements were taken from the middle of the double holes.

The distance between the bottom hole and the middle hole is 11.35 cm in the Sforziad, while in the drawing it is 11.06 cm.

The distance between the middle hole and the top hole is 11.7 cm in the Sforziad, while in the drawing it is 11.44 cm.

[MK] “15) The profile and the cartoon portrait of Isabella d’Este”

Above, Fig. 4: A comparison of La Bella Principessa with Leonardo da Vinci’s, Portrait of Isabella d’Este, c. 1499–1500, Paris, Musée du Louvre.

[KP] The portrait of Isabella d’Este shows the face in profile but the body in three-quarters, unlike La Bella Principessa. The former is also unfinished, rendered softly with the sfumato effect, fluid in execution, while the shading is on the inside of the profile.

La Bella Principessa is shown in full profile, highly finished, rigid and linear, while the shading is on the outside of the profile.

The similarities between the two profiles are only superficial.

The use of the word ‘repaint’ was an incorrect translation of the French word ‘repentir’, which means pentimento. I would like to mention that I have a good enough grasp of drawing techniques as I also trained as a copyist of Old Masters and an art restorer.

[MK] “16) Left-handedness”

[KP] I disagree that “the left-handed execution cannot undermine the attribution”, as it indicates the intention to imitate Leonardo. None of his collaborators or followers were left-handed, so the drawing is either by him or by an imitator/forger.

[MK] “17) The costume”

Above, Fig. 5: Comparisons of La Bella Principessa with Leonardo da Vinci’s, Head of a Woman, c. 1488–1490, National Gallery, Parma (left); Leonardo’s Portrait of a Woman in Profile, c. 1489–1490, Windsor Royal Collection (right); and, Gian Cristoforo Romano’s sculpture, Bust of Beatrice d’Este, c. 1491, Paris, Musée du Louvre (top).

[KP] The simplified and flatly rendered dress as well as the coazzone hairstyle do indeed show similarities with the sculpted busts by Gian Cristoforo Romano (Bust of Beatrice d’Este) and Francesco Laurana. But this could be a negative point, as the drawing could be based on one of these busts.

Incidentally, the opening in Laurana’s sculptures differs from that in La Bella Principessa. In the former it is a wide horizontal cut facilitating the movement of the arm, while in the drawing it is a triangular hole which doesn’t seem to play such a role.

Above, Fig. 6: Gian Cristoforo Romano, Bust of Beatrice d’Este, c. 1491, Paris, Musée du Louvre.

Above, Fig. 7: A comparison of the knots on La Bella Principessa’s dress and Gian Cristoforo Romano’s Bust of Beatrice d’Este, c. 1491.

[MK] “18) The fingerprint”

[KP] The fingerprint evidence which was originally published in the book as “strongly supportive of Leonardo’s authorship” is now considered invalid.

It was not possible to compare the palm imprint to Leonardo’s other examples, and it was described as perhaps unintentional as it is single and isolated, unlike in the execution of Cecilia Gallerani, where many imprints were found where the blending of hues had taken place.

[MK] “19) On Method”

[KP] The “accumulative build-up of different types of evidence” against the attribution to Leonardo is strong, but, as mentioned above, my main arguments were not addressed by Prof. Kemp.

Why is the shading on the outside of the profile? What is the significance of the hand writing on the reverse of the drawing and why was it not investigated? Why is the profile of La Bella Principessa so similar to that in the sculptural Bust of Beatrice d’Este by Cristoforo Romano? Why is the knot on the dress similar to the one on the bust and unlike other Leonardo’s knots? Why are the proportions of the face flawed? Why the vellum of the drawing was described as ‘rough animal hide’ and could it be part of the luxury book of the Sforziad? Why Marchig’s friend the famous Renaissance expert Bernard Berenson had not attributed the drawing to Leonardo? Why there is no known provenance prior to Marchig’s in the 1950s?

In the field of attributions the level of inconsistencies and contradictions always undermine any evidence in favour of a proposed attribution.

[MK] “20) The damaging allegation in the opening to Pisarek’s article that the owner was to set up ‘non-profit-making foundation for multi-disciplinary Classical and Renaissance studies near Florence, to be headed by Professor Martin Kemp’.”

[KP] I made no such allegation. This was a quotation from an article by Simon Hewitt who supports the attribution to Leonardo. This information was published in an Antiques Trade Gazette article by Simon Hewitt in 2009. The article can be found here.

In my article I also wrote: “Prof. Kemp and his colleagues are no doubt genuinely convinced of the authenticity of the drawing, as well as highly enthusiastic about the rediscovery.” This shows that I in no way question Prof. Kemp’s integrity on this matter, only the methodology and the results of the proposed attribution.

Kasia Pisarek, 24 May 2016