The Church was commissioned in 1254, outside the city walls (extra moenia), by the Augustine Friar Beato Lanfranco Settala who was later buried there. Vestiges of the original 13th century building are the Camionese ogival portal with above three statues of saints in niches in the façade attributed to the so called Maestro di Viboldone. In 1871 Carlo Maciachini built a new Neo-Gothic façade around the ancient entrance. The bell tower surmounted by late 19th century spires and the head of the Romanesque transept on the right are part of the original structure. The rest of the church now has a predominantly baroque aspect with a series of nine patrician chapels prominent along the right-hand aisle added on between the 14th and 19th centuries.
The interior is built on a Latin-cross plan with a nave and two side aisles divided by pillars where many works of art can be admired. Amongst these are frescoes from the sixteenth century by Palma il Giovane, Giulio Cesare Procaccini e Legnanino. A very large painting by Cerano depicting The Baptism of Sant' Agostino (1618) can be admired in the presbytery.
In the right transept are remains of fourteenth-century fresco paintings and imposing sculptures by Giovanni di Balduccio and the Maestri Campionesi from the same period.
The sacristy, furnished with carved wooden seventeenth century cupboards, leads to the Parish Museum where paintings torn from the lower part of the bell tower can still be seen together with other seventeenth century works. On the left side of the Church there is a wing of the cloister, restored in the seventeenth century, with memorial tablets of the patrician Archinto family.