(bapt. Siena, 23 Sept. 1439; bur. Siena, 29 Nov. 1501). Sienese painter, sculptor, architect, military engineer, and writer, a pupil of the equally versatile Vecchietta. He painted mainly during the early part of his career and few pictures certainly by him survive: the most important are a signed Nativity (c.1475) and a documented Coronation of the Virgin (1472–4), both in the Pinacoteca in Siena. As a sculptor, his major works are two bronze angels (1489–97) on the high altar of Siena Cathedral. Francesco was widely travelled, and his later career was spent mainly as an architect and military engineer (he was an expert in fortifications and is said to have exploded the first mine). As a technological innovator he was second only to his friend Leonardo, whom he certainly influenced.