Chiesa di Sant' Ignazio di Loyola (Church of St. Ignatius of Loyola), Rome

The Church of Saint Ignatius of Loyola at the Mars Field in Rome is a Baroque Latin Catholic titular church, dedicated to the founder of the Society of Jesus. Constructed between 1626 and 1650, it initially served as the chapel for the Roman College, later the Pontifical Gregorian University. This grand 17th-century preaching temple exemplifies the Counter-Reformation's architectural and religious fervor.

The church's history is rooted in the Roman College, established in 1551. Built on the land initially intended for a Poor Clares monastery, the available limited space prompted Jesuit architect Giovanni Tristano to complete a modest Church of the Annunciation in 1567. However, the church soon became inadequate for the college's growing student body.

After Ignatius of Loyola's canonization in 1622, Pope Gregory XV proposed building a larger church. His nephew, Cardinal Ludovico Ludovisi, commissioned Jesuit mathematician Orazio Grassi to design the new structure. Construction began in 1626 and culminated in 1650. The new church replaced the smaller one, occupying a quarter of the Roman College's block. Its Rococo square was added later.

The church's Latin cross plan, Corinthian pilasters, marble adornments, and gilded interiors mirror the Jesuit mother church, the Gesù. The grandiose frescoes painted on the nave ceiling by a Jesuit lay brother Andrea Pozzo, using the artistic technique called “deceive the eye,” create the illusion of a vast, open space, and are a major highlight.

Due to a lack of funds for a real dome, Pozzo painted an illusionary one, making the nave’s barrel vault appear as an idealized celestial vision where Saint Ignatius is received into heaven by Christ and the Virgin Mary. The artist's mastery of perspective, light, and shading gives the illusion of a towering cupola, visible from a specific marble disk in the nave floor. Another vantage point further east aligns with a second “deceive the eye” painting that depicts a tall, ribbed dome at the crossing— replacing the dome that was never built. The original painting, completed in 1685, was lost to fire, but in 1823, Francesco Manno faithfully recreated it based on Pozzo’s sketches and studies, preserving its striking visual deception.