The study of the many notebooks and papers that Leonardo da Vinci left behind upon this death has a long history. This study has included the careful examination of the papers he used, which now reside in collections around the world. The examination of the chain lines, laid lines, and watermarks has been facilitated by the availability of digitized images of the papers. These features have been computationally coded using an open-source suite of software available on this website, and reveal the existence of many papers likely made from the same papermaking mold, called moldmates. The findings presented on LEOcode.org contain the visual evidence and present images and overlaid animations of individual watermarks in Leonardo’s papers.

By inference, moldmates share a narrow production time and place of origin. The occurrence of cross-codex moldmates provides scholars with additional information that supports a historical connection between different codices.[1] Additionally, the numerous moldmates and their probable twins[2] found in different sources suggest new theories of their compilation and point to affinities among other of Leonardo’s papers.

To date, over twenty different watermark types[3] are represented by full or partial watermarks found in the Codex Arundel (MS 263, British Library)[4], the Codex Leicester (Gates Collection)[5], and selected Royal Collection Trust drawings. Computational coding of the watermarks has confirmed the presence of nearly 50 identical papers – called moldmates – that were formed using the same papermaking mold. Ten papers are cross-codex moldmates, that is, identical sheets that are shared between both codices, between the Codex Arundel and a Royal Collection Trust drawing, and found within a group of Royal Collection Trust drawings. These numbers are growing. 

The moldmates presented in this compendium represent ten watermark types: bull’s head, cardinal’s hat, eagle, flower, horn, scissors, the initials P and A in a circle,  mermaid, lily, and St. Catherine’s wheel. Each type is divided into subsets of recurring watermarks having different morphologies.[6] For example, the four kinds of eagle watermarks found are separated into Eagle – Group A, Eagle – Group B, Eagle – Group C, and Eagle – Group D. In each group, images from the individual sheets where the watermarks occur are included. For example, in Eagle – Group A, images from Leicester Sheet 1, 2, and 4 are shown.

For each group, a computationally enhanced or “de-noised” image of the watermark is included, as well as a simplified line drawing for rapid identification and comparison purposes only. The visible differences in each watermark group are further described. Live links to comparisons with Briquet watermark types, as recorded by Pedretti/Vecce[7] and others, are included for cross-referencing since Briquet watermark types are routinely noted in Leonardo literature and Briquet’s classification system remains useful as a taxonomic tool for describing watermark types.[8] It should be noted, however, that the traced watermark images found in Briquet and other watermark compendia cannot be used for moldmate matching.

The three watermark types (cardinal’s hat, flower, and eagle) shared between the two codices are presented first, followed by five additional watermark types found only in the Codex Arundel and listed in order of frequency (scissors, bull’s head, horn, initials P and A in a circle, and mermaid) and two (lily and St. Catherine’s wheel) found in the Royal Collection Trust drawings and the Codex Leicester and Codex Arundel, respectively. Additional watermark types found in selected Royal Collection Trust drawings have been added. Animated overlays dynamically confirm each moldmate match.

Notes:

[1] Gerolamo Calvi first dated the beginning of the compilation of the Codex Leicester to the years of Leonardo’s second stay in Florence. Il codice di Leonardo da Vinci (idraulica e cosmografia) della biblioteca di Lord Leicester in Holkham Hall, pubblicato sotto gli auspici del Reale Istituto Lombardo di Scienze e Lettere, Milan, Premio Tomasoni (Milan: L.F. Cogliati, 1909), vii-xviii. Among more recent dating proposals are those of Domenico Laurenza and Martin Kemp, who suggest that some of the material may date from as early as 1505 and that Leonardo “was still making additions after 1509, but not after 1512.” Leonardo da Vinci’s Codex Leicester: A New Edition, Domenico Laurenza and Martin Kemp, eds., 4 vols. (Oxford and New York: Oxford University Press, 2019-2020), 38-39. See also, Pedretti, The Codex Hammer of Leonardo da Vinci, 1987, and Carmen Bambach, Leonardo da Vinci Rediscovered (New Haven and London: Yale University Press, 2019), vol. 3, 273-274; also vol. 4, 292, note 438 and vol. 4, 352, note 557.

[2] A sheet made during the same run from a second alternating mold having the same type of watermark, although not precisely identical. See the section titled “What Are Paper Moldmates and Twins?” on the About page of this website.

[3] A watermark “type” is a generic category that typically includes different iterations of that watermark. For example, there are many versions of bull’s head watermarks found within the “type.” Because some watermark “types” were used over long periods of time and in different locales, they can encompass dozens of variations of the same basic design. 

[4] The dimensions of the opened bi-folios of the Codex Arundel are approximately 205 x 290 mm (8 3/32” x 11 14/32”); dimensions of individual sheets are unavailable. Their edges have been trimmed. Most of the opened bi-folios correspond to one half predominantly by folding in half a paper having a large rezzuta/reçute format, the same format as the sheets in the Codex Leicester. Eleven sheets found in the Codex Arundel have an unexpected orientation for a quarto, that is, their chain lines run parallel to the centerfold. This suggests that a larger format paper was cut down and incorporated into quarto-sized gatherings. These instances have been noted under their watermark entries; five sheets have no watermark. The folded paper is, in turn, folded in half again. In this arrangement, the sheet’s watermark is located in the centerfold of the manuscript, where it is less likely to be completely obscured by writing. Not surprisingly, due to the Codex Arundel’s quarto format, approximately half of its leaves contain a watermark.

[5] All 18 rezzuta/reçute format sheets of the Codex Leicester contain a watermark. The dimensions of the opened folios are approximately 300 x 400 mm (11 13/16” x 17 23/32”). Each open sheet is divided into four folios – two on the recto and two on the verso. Since many scholars refer to individual folios in the Codex Leicester rather than entire sheets, a concordance has been included which designates each folio according to traditional codicological syntax. A second concordance has been included that cross-references the ordering system devised by Carlo Pedretti in The Codex Hammer of Leonardo da Vinci, ed. C. Pedretti (Florence: Giunti, 1987). Watermarks found in the Codex Leicester are described by type and Briquet comparisons in Appendix IV, 181, of the same publication.

[6] A list of all watermarked leaves in the Codex Arundel, the Codex Leicester, and selected Royal Collection Trust drawings can be found under Browse by Source.

[7] Carlo Pedretti and Carlo Vecce, eds., Il Codice Arundel 263 nella British Library (Florence: Giunti, 1998).

[8] Because of its scope, relevance, accessibility, and long use within the discipline of traditional connoisseurship, Charles-Moi͏̈se Briquet’s work remains the standard watermark reference for drawing and print scholars despite its well-known limitations, specifically the inherent lack of accuracy and detail of watermark tracings made by hand and their different proportions in certain editions (noted below) and online. For a fuller discussion of Briquet’s significant contributions to the history of filigranology, see Neil Harris, Paper and Watermarks as Bibliographical Evidence, 2nd edition (Lyon: Institut d’Histoire du Livre, 2017), on the website of the Institut d’Histoire du Livre à Lyon (http://ihl.enssib.fr). Many editions of Briquet exist: Charles-Moi͏̈se Briquet, Les Filigranes: Dictionnaire historique des marques du papier dès leur apparition vers jusqu’en 1600. 4 volumes (16, 112 watermarks).

1. First edition Geneva: A. Jullien, 1907 (watermark images to scale).
   Online version: volume 1, volume 2, volume 3, volume 4
   Online database: briquet-online.at
   Database portal: Bernstein – Memory of Paper.
2. Second edition with a short biography of Briquet by John Briquet, Leipzig: K. W. Hiersemann, 1923 (watermark images to scale).
3. Facsimile of the 1907 edition with supplementary material contributed by a number of scholars: The New Briquet-Jubilee Edition / Charles-Moi͏̈se Briquet. General ed.: J. S. G. Simmons. Ed. by Allan Stevenson, Amsterdam: The Paper Publications Society, 1968 (watermark images to scale; https://d-nb.info/994361629).
4. Re-edition (facsimile edition of Leipzig 1923), New York: Hacker Art Books, 1985.
5. Re-edition (of Leipzig 1923 edition) in a reduced format, by Georg Olms Verlag. Zürich, New York: Hildesheim, 1991.
6. Re-edition (of 1907 edition) in two volumes, Geneva: A. Jullien von Martino Publishing, 200C