Sta. Stefano is a complex of several ancient churches and courtyards unified into one sprawling structure.
Partially built over a temple of Isis, parts of the original churches date from the 5th century. Now only
four churches and two cloisters remain, dating from the 11th-13th centuries.

This old Romanesque nave is part of the complex.
Each of the columns is different, and the barrel vaulted ceiling and thick walls with few openings are a hallmark of Romanesque architecture.