The Church of St. Peter Apostle, built in the medieval era, was completely rebuilt in 1755 by Giacomo Alamandini Bolognetti following 18th century architectural lines and a project by the famous architect Girolamo Theodoli, who also designed the Church of St. Peter and St. Marcellin and the Argentina Theatre in Rome.
The church has two very scenic facades, one facing the Palazzo Cenci-Bolognetti, the other facing the Temple of St. James.
A protruding cornice divides the facade horizontally: a large entrance portal, flanked by two small arches, in the lower part while the upper part holds a large rectangular window in the centre with two circular openings.
The interior is on a Greek cross floor plan. There are canvasses by Salvatore Monosilio – St. Peter entrusted with the flock by Christ over the main altar, St. Luke and St. Sebastian and the Nativity in the sacresty and four paintings of the lawyer saints in the transept: Athanasius, Roche, Sebastian and Anthony Abbot.