Avignon

Most of the building was done in the seventy years that Avignon served as the Vatican.

Avignon was part of the Kingdom of Arles in southern France and was included in the Papal States as well as a good portion of mid-to-northern Italy at the time. The French kings weighed in and the Vatican moved to Avignon in 1309. There were seven popes at Avignon. Gregory XI was the last and moved his court back to Rome. Two more French popes tried to establish themselves at Avignon and failed. Quite the medieval site!

Wikipedia