The alterpiece was made for the main altar of the church - consecrated by Pius II in 1462 - of the grange, a fortified farm of the Hospital of Siena in Spedaletto, not far from Pienza. It was commissioned by Niccolò Ricoveri and Floriano di jacopo, respectively rector and treasurer of that great Sienese institute. Each of their onomastic saints appear in the main register to the left of the Virgin, while the other saints, John and Biagio, alluded respectively to the baptismal function of the church and to an important reliquary possessed by Sienese hospital. The attention to perspective and the luminosity of the composition testify an interest in Domenico Veneziano, while the fierce-looking Baptist appears to allude to the celebrated bronze statue that Donatello had left in the Duomo of Siena in that same period. The format of the painiting imitates the Renaissance carpentry of altarpieces commissioned by Pius II for the Cathedral of PIenza, but this one is different since it replaces the traditional gold background instead of realistic ones. The lunette show the Annunciation; the predella, along the sides, depicts the emblems of the Sienese Hospital of Santa Maria della Scala and the Martyrdom of Saint Biagio, the Crucifixion and Saint Nicola giving alms to three young maidens.