Although the present Church of St Maurice at the Greater Monastery, with its slabbed polychromatic façade, was constructed in the beginning of the 16th century, there had already been structures standing on this spot since the Ancient Roman period. Today we can find a polygonal tower near the church, which was part of the Maximian wall from the late 3rd century A.D.
Saint Maurice was the leader of the famous Theban Legion. This was a legion of 6,666 Roman soldiers, all Christian, which was dispatched by Emperor Maximian to quell a peasant revolt. Many of the peasants were also Christians and when the legionaries were ordered to harass them, they refused. Maximian thus ordered the legion to be decimated, that is, have every tenth soldier executed. The legion, encouraged by Maurice, still refused to touch the Christian peasants and at that point the emperor had all the members of the military unit executed. It was a mass martyrdom.
Three architects worked on the current church: Gian Giacomo Dolcebuono, Gianantonio Amadeo and Cristoforo Sorai. The structure was divided into two parts: one for the churchgoers and one - a convent - for the nuns, who until 1794 were not allowed to cross the dividing wall. Originally, the church was part of the Monastero Maggiore, Milan's most prominent Benedictine convent at the time. Today that convent is used for the neighboring archeological museum.
Although architecturally the Church of St Maurice does not appear very spectacular, except that the vaulted nave is curiously divided by a partition, there are some captivating pictorial works that can be found throughout the edifice. The most important is a series of frescoes showing the Life of St Maurice by Bernardino Luini, located in the space called the Hall of the Faithfuls, right behind the main altar on the partition. The altarpiece featuring the Adoration of the Magi is a work by Antonio Campi.
There are four chapels on each side of the church. They contain frescoes painted by Bernardino Luini's sons, Aurelio, Gianpietro and Evengelista. The most expressive is the fresco in the Chapel of St John the Baptist, third on the left. The Chapel of St Catherine of Alexandria has a fresco by Bernardino showing Catherine kneeling down in prayer with her bosom disrobed.
The Hall of the Nuns has a frescoed ceiling by Vincenzo Foppa depicting the Blessing Eternal Father and Angels amidst a starry blue sky. This hall also contains Bernardino's Deposition from the Cross and his son Aurelio's Stories of Noah's Arc. Of particular interest is the 16th century pipe organ, built by Gian Giacomo Antegnati.