On the left-hand altar is the canvas showing Saint John the Baptist in the Desert, datable around the 1580s. This work, also by Francesco Vanni, came from the ancient church of the Santissimo Salvatore. The painting is characterized not only by chromatic and formal elegance, but also by the mystical vein typical of Vanni’s art. The scene is set in the desert, the place where John the Baptist preached about the coming of the Messiah: “After me is coming someone who is more powerful than me, and I am not fit to kneel down and undo the strap of his sandals” (Mark 1:7). John the Baptist is also identifiable by his iconographical attributes: the wayfarer’s staff with a cross and the inscription “Ecce agnus Dei” (“Behold the Lamb of God,” John 1:29); the tunic made of “camel-skin, with a leather belt around his waist” (Mark 1:6) and a red mantle, symbol of his martyrdom (from the Greek μάρτυς, “witness”), since martyrdom was the last act by which John the Baptist fulfilled his role as precursor of the Messiah, who would die on the cross.