The Collegiata di Santa Maria Maggiore (Collegiate Church of Santa Maria Maggiore) we see today is the result of restoration works carried out in 1675 by the will of Duke Filippo Cesarini. Little remains of the pre-existing Romanesque church of 1240 as most of the marble decorations and the coloured floor tiles were destroyed during the same restoration work.
However, during further work carried out to repair the damages caused by Second World War bombings, remains of a Roman domus were found beneath the Romanesque church. Fragments of a splendid polychrome mosaic from the 4th century can be seen in the actual church today.
It has seven altars and the central one is decorated with a painting by Baciccia depicting the Calvario (Calvary). Particularly interesting is the canvas illustrating the Deposizione della Croce di San Filippo (Deposition of the Cross of St. Philip the Apostle) by Domenichino, as well as the bell tower designed by Tommaso Mattei, Fontana’s apprentice.
Up to the 19th century, it was the seat of three confraternities, the Holy Sacrament, the Sacred Rosary and the Crucifix.