The San Nazaro in Brolo basilica is one of the four extramural churches commissioned by bishop Ambrogio because of the increasing amount of Christians in Milan. It was the second one to be built, and it was flanked by a porticoed street, the current Corso di Porta Romana. The basilica, which houses the relics and the sepulchre of martyr Nazaro, originally had a Latin-cross plan with a rectangular apse.
It was destroyed in 539 by the barbarians under Uraia and in 1075, due to a fire that burnt down the ancient centre of Milan, so its restoration was commissioned by Carlo Borromeo in 1571: new windows and doors were created, some chapels were demolished and the Romanesque altar was removed. The San Nazaro basilica underwent other changes, the latest one conceived by architect Villa, between 1946 and 1963, due to the damages caused by bombings during World War II.
The church houses artworks such as “Annunciazione” by Daniele Crespi, “Gesù nella passione” by Bernardino Luini, “Crocifissione” by Bonino da Campione, “Ultima cena” by Bernardino Lanino, “Presentazione di Gesù al tempio” by Camillo Procaccini. The relics of Saint Nazaro are kept underneath the main altar but the original burial-place is showed by a marble gravestone in the presbytery.