Designed by Giacomo Della Porta in 1589 and built by Pompilio De Benedetti, the fountain consists of an octagonal travertine base on which rests a cup with the same shape. The cup bears on six sides the insignia of the Senate and the coats of arms of the four families (Capizucchi, Albertoni, Muti, and Ricci) that had financed the work, and on the remaining sides two large masks pouring water. At the centre of the pond a shaped shaft supports a portasanta marble circular basin that pours water. The fountain was originally placed at the centre of the square in front of the church of Santa Maria in Campitelli and by disposition of Innocent the Eleventh Odescalchi (1676-1689) it was placed on one side of the square after it was enlarged in 1679 to prevent the persons that met around it from bothering the religious ceremonies with their “free talking”. In 1927 the fountain was restored by the architect Raffaele De Vico.