Built in Baroque style between 1626 and 1650 in honour of St. Ignatius, who was the founder of the Society of Jesus (also called the Jesuits), the church functioned originally as Rectory church to the adjacent Collegio Romano, that moved in 1584 to a new larger building and became the Pontifical Gregorian University
The church has a Latin cross plan with six side chapels. The building was inspired by the Jesuit mother church, the Church of the Gesù in Rome.
The most striking aspect of this church is the cupola which was never built and in its place,in 1685, Andrea Pozzo supplied a painting on canvas with a perspectival projection of a cupola. The effect is that of the appearance of a real three dimensional cupola.