LONDON.- Museo Galileo, the Italian Ministry of Culture and the Embassy of Italy in London announce the reunion of two globally significant collections of Leonardo da Vinci’s writings and drawings for the first time in over 400 years in a new online platform. Leonardotheka launches today, 8 June 2026, at teche.museogalileo.it/leonardo, and constitutes the most extensive resource on Leonardo da Vinci's manuscripts in the world.

Marking the culmination of a 10-year project in collaboration with Royal Collection Trust, Windsor, the Veneranda Biblioteca Ambrosiana, Milan, and the Biblioteca Leonardiana in Vinci, a dedicated group of Leonardo scholars and digital experts has worked to bring approximately 3,500 pages of manuscripts back together after they were separated and cut into pieces in the late 16th century.

Leonardotheka reveals new insights into Leonardo’s thoughts, vision and working process through the ambitious reconstruction of select pages, digitally restoring their original appearance, to make clear the intended connections between scientific texts and figurative drawings, which had been arbitrarily separated by a later collector.

Museo Galileo initiated this collaboration between partner institutions – convening the world’s leading scholars and knowledge accumulated over centuries of study – with the primary goal of broadening access to Leonardo's rich legacy via a public platform.

Leonardotheka reunifies the 1,119 sheets of the Codex Atlanticus – the largest single set of Leonardo’s writings, held bythe Veneranda Biblioteca Ambrosiana – with the most important group of figurative, anatomical, landscape and natural-history drawings by Leonardo in existence – around 550 sheets, part of the Royal Collection at Windsor Castle. These two collections – originally from the same set of manuscripts made by Leonardo from the mid-1470s to just before his death in 1519 – are now brought together in a cross-searchable digital resource.

Following Leonardo’s death, Francesco Melzi – Leonardo’s final student – inherited his entire collection of manuscripts. They then came into the possession of Italian sculptor Pompeo Leoni who dismounted and cut the folios, separating the materials into two albums according to his own judgement: the larger portion for technical and scientific topics; the other for Leonardo's artistic and figurative workings. In the early 17th century, Polidoro Calchi, Leoni’s son-in-law, inherited the manuscripts. He sold the most substantial album, later named Codex Atlanticus, to Count Galeazzo Arconati, who donated it to the Veneranda Biblioteca Ambrosiana in 1637. The other album containing the figurative works was brought to England in the 1620s and entered the Royal Collection around 1670, probably as a gift to Charles II.

Leonardotheka includes 50 confirmed page reconstructions, in which small page fragments held at Windsor have been returned to the pages of the Codex Atlanticus to restore their original context. This complex task involved examining the dimensions and preparation of paper, use of writing media and watermarks – all of which are available filters within Leonardotheka. One notable reconstruction (reuniting folio 399r of the Codex Atlanticus with folio 912345r from Windsor) brings together a drawing of a horse with a written reflection on the classical Regisole equestrian monument in Pavia. This likely represents the moment that Leonardo conceived the final sketch for the horse intended for the ambitious, never completed Francesco Sforza equestrian monument.

Leonardotheka’s advanced tools allow users to navigate the labyrinth of Leonardo's papers with detailed data on physical and material properties (watermark imaging and digitisation by Haltadefinizione) and writing and drawing techniques; links to related sheets; transcriptions; critical commentaries; thematic indexes; and bibliographies, including links to items available in Museo Galileo's digital library.