Probably built on a pagan cemeterial area, the church was completed around 1260 to host the Humiliati friars and, after the suppression of the order in 1571, it was assigned to the Barnabites.
Of the original medieval construction only the bell-tower and the perimeter terracotta walls remain, along with the lively and elegant series of 18th century religious buildings overlooking the square.
Inside, the frescoes on the central nave ceiling and the paintings on the walls by Lombard artists are very valuable. Of consideration is also the sandstone portal by Buzzi (1731) depicting St. Paul.
The complex is completed by a cloister, a library containing the important book holdings of the convent and a theatre.