At the corner of Via dello Sprone and Borgo San Jacopo, it was realized by Bernardo Buontalenti at the beginning of the 17th century, probably on the occasion of the passage of the wedding procession of Cosimo II de’ Medici, as seems to be confirmed by the coat of arms with the six balls just above the fountain. From the mouth of the mask, a sort of faun, sculpted in marble and placed on the spur of the palace, comes out a jet of water that falls into the first basin, immediately below, also in marble with wide lateral volutes as if it were the shell of a seashell. From here the water overflows like a waterfall into the basin on the ground, made of stone, from where it then flows. In this way men and animals can and could drink and refresh themselves.