Francesco di Giorgio Martini (1439-1501)

Born in Siena, he was an architect, engineer, painter and sculptor. His pictorial masterpieces, such as the Coronation (1472) and the Nativity (1475), are now in the Pinacoteca of Siena.
Leonardo studied his treatises (marginal notes in the Ashburnam Ms. in the Laurentian Library in Florence, and passages copied in Madrid Ms. II, during his time in Piombino) and was with him at Pavia in 1490.
Some of Leonardo's autograph drawings, including that of the "Etruscan mausoleum", now in the Louvre, were attributed to him in the past.
Recent attempts have been made to assign Leonardo a very important role, although not yet proven, in Francesco di Giorgio's architectural works, such as Santa Maria delle Grazie at Cortona. It is more probable instead that Leonardo was influenced by him.