This occupies the  place where the ancient Church of St. Ambrose was and it is quite possible that there still remain some of the outlines of that Church. The Altar, transferred here from the ancient Oratory in 1702, had, in its central arch, "The Immaculate Conception flanked by SS. Ambrose and Charles in Pontifical Vestments" (cf. Papal Sacristy). The two Sibyls refer to the mystery of the Immaculate Conception, a work of Tommasi della Porta who donated it to the Confraternity in 1583 together with the magnificent group of the "Deposition" which today is rightly the titular of the Altar. The work is an excellent example of late Mannerism. During the 1930's the whole Oraty was redecorated under the direction of Cardinal Caccia Dominioni.