The church of San Maurizio al Monastero Maggiore in Milan is the church of a Catholic convent. A religious enclosure, known as a rood screen or tramezzo, separates the church from its congregation and the choir of the convent, where the cloistered monks once attended Mass and communicated through a wicket. The convent also provides access to archaeological excavations of ancient Roman fortifications. Construction of the church began in the early 16th century. It is richly decorated with frescoes by a number of important painters of the period, including Bernardino Luini, a pupil of Leonardo da Vinci, Antonio Campi and Simone Peterzano.