This church is of very ancient origin, being mentioned as early as the 7th century. It was indeed known as the 'church of the Milanesi', as the church was originally dedicated to Ambrogio, bishop of Milan, who fled to Genoa to escape the sack of the city by the Lombard king Alboino.

The basilica was then entirely rebuilt by the Jesuits at the end of the 16th century. It was originally designed by the Jesuit architect and painter Giuseppe Valeriano, who also designed the Gesù Nuovo church in Naples.

The present façade, clad in Finale stone and marble, dates back to 1894, while the bell tower is from the early 20th century.

The church's interior is entirely decorated with prestigious polychrome marble and it is a valuable example of Genoese Baroque. The vaults were frescoed by the Carlone brothers during the 17th century, and in the same period, noble Genoese families commissioned altar pieces to great European artists.

On the main altar is the Circumcision by Pieter Paul Rubens (1605), which will have a great influence on local painters for its use of light and a new idea of movement. The left aisle hosts the altarpiece of Saint Ignatius Healing an Obsessive Woman, also by Rubens, while the right aisle hosts the Assumption by Guido Reni. 

Not to be missed are also paintings and frescoes by many prominent painters of the Genoese school and others. These include Domenico Piola, Domenico Fiasella, Valerio and Bernardo Castello, Giovanni Andrea and Lorenzo De Ferrari, Domenico Scorticone, Andrea Pozzo and Simon Vouet among others.