Leonardo showed his interest in the Etruscan city of Cortona on maps RL 12278 and RL 12277 (Windsor Castle). He also mentions it twice on map RLW 12682 for the measurement of distances: «from Castiglione to Cortona 5 miles» and «From Foiano to Cortona 8 miles ».
The importance of the watercourse that passed near Cortona on its way from Val de Chiana to Trasimeno is reflected in a note on one of Leonardo’s maps (RL 12278): “Branch of the Montone [River] cuts it off so that it no longer exists”.
In the Etruscan Academy Museum is displayed the Muse Polymnia, a painting on slate once considered a Roman work, today deemed a Renaissance falsification, perhaps related to Leonardo's rediscovery of the "encausto " pictorial technique, or, according to others, an eighteenth-century work inspired by the coeval Pompeian discoveries. In the Etruscan Library is a seventeenth-century copy of the Book on Painting, (Ms Zuccari, 297): "Opinion of Leonardo da Vinci. Method of painting perspectives, shadows, distances, heights, depths from close up, from afar, and other things".