The church called Collegiata di San Giuliano – dedicated to San Giuliano Ospitaliere, the Patron Saint of Faleria - was built on the foundations of a 12th-century building whose remains are still visible in the exterior walls. The current layout dates back to the 13th century.

Over the centuries the church underwent several renovations therefore not much is left of the original 13th-century building, a part from a section of the marble floor  - by the main portal - that shows a Cosmati style.

In recent times, some frescoes have been discovered and restored. They are inside the church, by the apse, and they depict San Giuliano with Stabia – Faleria’s ancient name – and Rome in the background.