The notes of the organ accompany the various moments of the liturgical celebration. Dated 1522, it is, along with the one in the church of Santissima Annunziata, one of the finest works by the famous Sienese organ-maker Giovanni Piffero. Originally set on the left wall of the nave, at the corner of the transept, it is now in the loft above the entrance portal, where it was moved perhaps because of . . .