The seat of the Archbishop of Aix. It is built on the site of the 1st century Roman forum of Aix. Built and re-built from the 12th until the 19th century, it includes Romanesque, Gothic and Neo-Gothic elements, as well as Roman columns and parts of the Merovingian baptistery from a 6th century Christian church. It is a national monument of France. The interior has a double nave and houses the masterpiece by Nicolas Fromen, the Burning Bush Triptych.