In the south transept the beautiful window over the door into the street is mainly the work, much mutilated and added to, of Michelino da Besozzo in 1438. Here on the west side is a great monument by Leone Leoni of Arezzo, a disciple of Michaelangelo, to Gian Giacomo de’ Medici, brother of Pius IV., a princely pirate who terrorised Lake Como and led his undisciplined troops in the service now of one, now of the other of the combatants struggling for North Italy in the sixteenth century, till Charles V. compounded with him by creating him Marquis of Melegnano. On the east side is an altar with a relief of the Presentation of the Virgin, and statues by the school of il Bambaia. A statue close by representing St. Bartholomew flayed is admirable only for the impudence of the inscription on it—‘_Non me Praxitiles, sed Marcus finxit Agrates._’ Marco Agrate was one of the crowd of early sixteenth century Lombard sculptors who helped to people the Duomo with statues. This one was originally on the exterior of the church. The choir in its present form is due to Pellegrini, whose assistants executed the grandiose work after his designs. It is enclosed by a high marble screen, which is sculptured on the side towards the ambulatory with reliefs of the life of the Virgin and decorative figures of late Renaissance style. Two extremely ornate gilded pulpits stand in front of the choir, one on each side. The organs are embellished with heavy gilded decoration and paintings by Proccacini and the late Lombard school. The choir has very fine decorative panelling, and the triple row of stalls are of walnut wood very richly carved, those behind showing scenes from the story of St. Ambrose and effigies of the martyrs and saints and prelates of Milan. The bronze ciborium over the altar is a good work of its period; it is in the form of a round temple, and beneath is the richly-ornamented tabernacle given by the Milanese Pope, Pius IV. (1559-65), to the Cathedral. Beneath the choir is the crypt, also built in classic style by il Pellegrini. The outer chamber was restored in 1817. In the inner sanctuary lies the body of San Carlo in a silver coffin given by Filippo IV. of Spain. Vault and coffin are remarkable only for gorgeousness. Pomp and magnificence outside, an emaciated ascetic within, contrast significant of the Church of the Catholic Revival. An aperture in front of the choir above allows a view of the saintly resting-place.