How a fake Kepler portrait became iconicSteven N Shore ID 1 amp Vaclav Pavlık ID 2

1 Dipartimento di Fisica Universita di Pisa Pisa Italy2 Astronomy Department Indiana University Bloomington Indiana USA

To appear in an edited form in Readersrsquo Forum Physics Today (September 2021)

Textbooks and popular writings introduce portraits ofhistorical personalities to illustrate the human side ofscience Usually they get it right Einstein did stick outhis tongue to reporters Marie Curie really did dress inblack and Oppenheimer wore a fedora But for the lastfew decades one of the founders of modern physics andastronomy has been portrayed with a fake Since thisyear marks the 450th anniversary of Johannes Keplerrsquosbirth it is timely and necessary to point out an egregiousexample of unwittingly propagated misinformation

The portrait Fig 1a that is now the first entry onGoogle search for ldquoKepler portraitrdquo (where it has overseveral thousand entries ndash including variations such ascartooning and mirroring ndash and appeared as a front pageGoogle doodle on December 27 2013 and even more re-cently as the cover of Giornale di Fisica Vol 62 April2021 which is addressed to high school physics teachers)is in the possession of the Kremsmunster Benedictinemonastery in Austria In the earliest citation we know[1] the acquisition of the painting is described as a saleto the abbot of this monastery in 1864 A more completedescription is provided in 1898 by Gunther [2] He statesthat ldquoAccording to the notes I owe to P Hugo Schmidthe monastery librarian there the painting belonged toa notary Gruner who passed it on in 1864 to the currentabbot of the monastery Reslhuberrdquo The painting wasdescribed as a copy of an original in possession of the de-scendants of Keplerrsquos siblings [1] Neither the artist northe identification of the presumed original were providedin any of the sources The current painting is an oil onoak panel (37times50 cm) with no signature or attributionThere is only the Latin phrase ldquoAetatis Suae 39 1610 rdquoin the upper right corner (which usually appears croppedin the photographs) The painting was discussed in the1930 Kepler Festshrift by Zinner in a general summary ofKepler iconography [3] He notes that the painting wassold to the abbey for 200 gulden and that Gruner wasfrom Weil der Stadt (Keplerrsquos birthplace) Zinner alsosummarizes the previous descriptions calls the paintingan ldquoalleged portraitrdquo and notably includes the opinionof experts who examined the painting in the 1920s Al-though there is no published physical analysis Zinnerreports that Professor Seraphin Maurer of the ViennaAcademy of Fine Arts stated that although this picturegives the the overall impression to be from the 17th cen-tury ldquo[h]owever on closer inspection the technical treat-ment shows that the painter had no understanding ofportraiture [ ] Furthermore the colors have not yetfaded which is always the case with pictures from that

time There are no visible signs of aging such as cracksso I assume that the picture might have appeared around1800 (a little earlier or later) The oak panel also hasa finish that is not the usual type from around 1600These are the main features that enable me to state thatthe picture is a copyrdquo Even before reading Zinner [3] wehad long suspected that the painting could not be fromearlier than the 19th century for stylistic reasons and wewere quite pleased to find that Zinner and his informantsreached the same conclusions

More to the point the portrait in Fig 1a is likely noteven Kepler but we will argue that it is a 19th centuryforgery that could be based loosely on an official aca-demic portrait from life of Michael Mastlin (see Fig 1b)Keplerrsquos teacher and promoter It is enough to comparethe details in the two portraits

We contend that this alleged painting of Kepler if itis based on anything other than fantasy could easily bea corruption of the Mastlin portrait Anyone knowingKeplerrsquos dates could compose the inscription The dressis wrong for the period and does not accord with thetwo certain historically flanking portraits of Kepler ndash thecommemorative medallion from his wedding in 1597 andhis official portrait from 1620 (see Fig 1c) In neitherdoes he wear an academic gown Although certainly notdeterminant it would be somewhat surprising for Ke-pler at that time in the court to wear the formal collarworn by noblemen and professors of the period as in theMastlin portrait A lace collar (as in Keplerrsquos official por-trait) would have been appropriate An alternate candi-date for the presumed original subject could be WilhelmSchickard who was a contemporary and a collaborator ofKeplerrsquos but in 1610 he had yet to enter the academicworld so there would be no reason for the portrait

There is another presumed portrait of Kepler fromaround 1610 which since the 1973 has been attributed toHans von Aachen one of the favorite painters of Rudolf IIand a contemporary of Kepler in Prague [4 6 7] seeFig 1d These two portraits cannot be simultaneouslythe representation of the same person Although theidentification is still disputed at least in the case of vonAachen the artist is known and the painting is originalFinally another painting identified as Kepler known asldquothe Linz portraitrdquo [5] is dated to 1620 see Fig 1e Al-though the artist is unknown as already noted in theliterature it does resemble the representation of Keplerin the frontispiece of the contemporaneous RudolphineTables [8] and Keplerrsquos official portrait from the sameyear but here Kepler wears the Spanish collar This is

Preprint version created by the Authors in LATEX 1

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Shore amp Pavlık How a fake Kepler portrait became iconic

a) b)

c) d) e)

Figure 1 a) Fake Kepler portrait A 19th century painting by an unknown artist presumed to be a copy of an unknownoriginal allegedly from 1610 If it is based on anything it more likely derived from a portrait of Michael Mastlin b) MichaelMastlin portrait A black and white photograph of an original from 1619 by an unknown artist University of Tubingenalso flagged by Zinner [3] as a possible source for the fake c) Johannes Kepler portrait An engraving based on the 1620Kepler portrait that was given to the Strasbourg library in 1627 (Courtesy of the Smithsonian Libraries and Archives ImageID SIL-SIL14-k001-08 httpslibrarysieduimage-gallery72833) d) Presumed Kepler portrait Attributed toHans von Aachen [4] It is assigned around the same year as the fake portrait likely 1612 e) The Linz miniature PresumedKepler portrait from 1620 artist unknown [5] (Courtesy of the Oberosterreichisches Landesmuseum Linz)

however a miniature [5] not an official portrait and thefashion was much more common in Europe at that time

So our final question is how did this contagionspread Before 2000 we cannot find any examples ofthe portrait being used to represent Kepler except forour cited references However 2001 saw the founding ofWikipedia and the portrait appeared there for the firsttime in 2005 Thereafter it becomes ubiquitous Forexample it appears in the ESA press release from 2011(explicitly citing Wikipedia) ESO attached it to an ar-ticle from 2016 and NASA used it in their Solar Systemeducational material in 2017

While this may just seem like a trivial byway imagesfix in the mind Kepler deserves better

References

[1] R Wolf Geschichte der Astronomie page 281 R OldenbourgMunich 1877

[2] L Gunther Keplers Traum vom Mond B G TeubnerLeipzig 1898

[3] E Zinner Bericht des Naturwissen Verein Regensburg 19337 (1930)

[4] T D Kaufmann The school of Prague Painting at the courtof Rudolf II page 154 University of Chicago Press Chicago1988

[5] G de Somzee and B Ulm Jahrbuch des OberosterreichischenMusealvereines 118a 161 (1973)

[6] O Gingerich IAUTA 15A 642 (1973)

[7] D Jansova Kapitoly z dejin sberatelstvı na Kolowratskemzamku v Rychnove nad Kneznou Filozoficka fakulta Uni-verzita Palackeho v Olomouci 2014

[8] H-J Albinus and D Suckrau The Mathematical Intelligencer43 64 (2021)

Preprint version created by the Authors in LATEX 2

Shore amp Pavlık How a fake Kepler portrait became iconic

Note after acceptance

After placing the preprint on arXiv we were contactedby Dr Alena Solcova who pointed out several typos inthe original arXiv version and suggested that we alsoinclude the Linz miniature

We were also fortunate to have been contactedby Dr Anders Nyholm who very kindly provided re-productions of two notices of this painting predat-ing the earliest we knew One is the catalogue entryfor the Vienna Worldrsquos Fair (Welt-Ausstellung 1873in Wien p 821 group 14 ndash Scientific Instrumentsno 3 httpssachsendigitalwerkansichttx_

dlf[id]=17012amptx_dlf[highlight_word]=Kepleramp

tx_dlf[page]=835) where the the source is listed asldquoResslhuber Abt Dr Kremsmunster Portrat JohanesKepler (1610)rdquo (spelled with two lsquosrsquo and one lsquonrsquo) andno further information The second citation is an aes-thetic appreciation from the Neue Freie Presse (WienDonnerstag October 2 1873 p 4 Nature and Eth-nology httpsannoonbacatcgi-contentannoaid=nfpampdatum=18731002ampquery=22Kepler22ampref=

anno-searchampseite=20) It is noted that Reslhuberprovided the portrait It appears that he was convincedthat the portrait is real and was proud of the acquisition

Preprint version created by the Authors in LATEX 3