Master of the Osservanza Triptych

The Virgin and Child with St. Jerome and St. Ambrose (Basilica dell'Osservanza, Siena) and the Birth of the Virgin (Museo d'Arte Sacra, Asciano) are both stylistically similar to the work of Stefano di Giovanni, but have a narrative expression that is characteristic of Late Gothic painting.

Longhi observed that another group of paintings was closely related to these works and appeared to be by the same hand.

Additionally, the full-length painting of St. Anthony Abbot in the Louvre appears to be from another altarpiece by the same master.

Research in 2010 by Maria Falcone in Siena has revealed the name of the Master to be Sano di Pietro.

Falcone found a document about an altarpiece by the “Master of Osservanza” for a church in Asciano, just outside Siena, which was actually under the bishopric of Arezzo.