A series of drawings of views of an equestrian monument; with a ground plan of the columns of the monument; a diagram concerning optics; a diagram of cog-wheels and gears; a sketch of a mill, and some notes. The sketch of the monument on the upper part of the sheet (formerly mounted separately as RCIN 970125) is a fragment from the Codex Atlanticus, folio 83 verso-b. It was reattached to the sheet in January 2018. Melzi's number 18 and 41.

While in the service of Ludovico Sforza around 1490, Leonardo had spent almost ten years working on a huge equestrian monument to Ludovico’s father, only for the project to be abandoned. Twenty years later Leonardo designed another equestrian monument, to Gian Giacomo Trivulzio, who had led the French forces in the invasion of Milan in 1499. The monument was to consist of a bronze horse and rider surmounting a marble architectural framework housing Trivulzio’s sarcophagus. Leonardo’s costing for the final design survives, but there is no evidence that he carried out any physical work on the monument.

On this sheet Leonardo sketches out grandiose ideas for the base – a circular structure with an inner drum rising above a ring of columns; a vast two-storeyed confection; or a four-sided classical structure opening onto the sarcophagus. The fragment mounted at upper centre shows the horse and rider placed directly on a sarcophagus.

Text adapted from Leonardo da Vinci: A life in drawing, London, 2018