For this altarpiece the painter was paid in 1326: it was executed for the residence of the Capitano del Popolo and only later - after 1405 - was placed on the altar of the sumptuous Cappella dei Signori on the first floor of the Palazzo Pubblico in Siena, next to the famous Sala del Mappamondo. It included the figures of St Peter and St Ansano, the protector of the city of Siena (on the left), the Virgin with Child (at the centre) and the figures of St Andrew and St Luke (on the right). The five panels composed a polyptych of a rather unsual shape, with the central panel of the same size as the side panels, and with each element independently framed.
In the fifteenth century, Sano di Pietro painted five panels with Stories from the Life of the Virgin, which were placed as a predella below each of the panels by Simone Martini. The altarpiece of the Cappella dei Signori was disassembled in 1686, the panels are now in various museums.