(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. Among his patrons was Federico da Montefeltro, and Francesco may have had a hand in the designing of his celebrated palace in Urbino. His also designed churches, notably S. Maria del Calcinaio, near Cortona, begun 1484. Francesco wrote a treatise on architecture in the last years of his life; it was not published until 1841.