Jesuit style, inspired by the Gesú of Rome, mother church of the Jesuits. Latin cross plant, with short arms. The central nave (33.80 m. Long, 9.25 m. Wide and 20.80 m. High) has a half-barrel vault, resting on an entablature of the Ionic order, whose frieze is adorned with a Simple and elegant geometric border.
On each side of this central nave there is a lower lateral nave with chapels. The transept ends with a half-orange dome (36 meters high and 10 meters in diameter). This dome has eight funnel-shaped windows, and rests on pendentives. In these there are polychrome angels that hold the cardinal’s shield with one hand and in the other a monstrance with the anagram of the name of Jesus. The dome culminates with a beautiful lantern with six large windows that provide abundant light to the church.
The church was completed in 1619 (architect Simón de Monasterio), and consecrated the same year. Dome and skylight or lantern have been damaged by the passage of time and, above all, by the Lisbon earthquake of 1755.