As a bonus, the wonderful Museo Archeologico is also part of the monastery complex, and while we definitely intended to see both during this visit, our primary goal upon arriving was to visit this church that is said to be "Sistine Chapel" of Milan! So after entering the monastery complex, we immediately headed to the doorway on the left which accessed the church.
The Monastero Maggiore was built partially re-using ancient Roman structures including a polygonal tower, a relic of the ancient walls built by Emperor Maximian (c. 286 to 305), and a square tower, originally part of the lost Hippodrome. This tower was later adopted as the church’s bell tower.
Chiesa San Maurizio is divided into two parts: one for the faithful congregants, and one for the nuns. The nuns would have been constrained to listening to the mass through a grated partition. The nuns were strictly forbidden to leave their cloistered area.
The partition wall divides the church into two halls: a large hall with six bays for the nuns living at the convent (Hall of Nuns) and a smaller public hall for the congregation (Hall of Believers). The Hall of the Nuns is where the choir is located. It is also home to the organ built in 1554-1557 by Gian Giacomo Antegnati. The organ's case was decorated by Francesco and Girolamo de' Medici da Seregno.
The most famous of the paintings are the frescoes of Bernardino Luini, a student of Leonardo da Vinci.
Luini’s frescoes in the St. Catherine chapel in the Hall of Believers and on both sides of the partition wall are among the most celebrated works of art in Milan. The dividing wall has frescoes depicting the Life of San Maurizio which flank the main altar which has a painting of the Adoration of the Magi by Antonion Campi.
The museum exhibits begin with displays showing artifacts from ancient Milan, including several beautiful mosaics.