Piero della Francesca (c. 1415 – October 12, 1492) was a painter of the Early Renaissance. As testified by Giorgio Vasari in his Lives of the Artists, to contemporaries he was also known as a mathematician and geometer. Nowadays Piero della Francesca is chiefly appreciated for his art. His painting was characterized by its serene humanism, its use of geometric forms and perspective.
Piero della Francesca, 7a. Finding of the True Cross (detail) 1452-66 Fresco, San Francesco, Arezzo