The Master of the Osservanza is the name given to the painter of a triptych dated 1436 in the Osservanza near Siena. The triptych is closely connected with Sassetta and in the past was attributed to him.
Some critics have thought this work and a group of other pictures now attributed to the Master to be youthful works by Sano di Pietro, but this is not generally accepted.
Master of the Osservanza
active about 1425 - about 1450