Along with Notre-Dame de Nazareth Cathedral, the Count's castle of Vaison-la-Romaine is part of the two listed sites of the city's medieval period. Its construction, born from a conflict between the secular power of the Count of Toulouse and the episcopal power of the bishops of Vaison in the 12th century, was the starting point for the displacement of the population from the right bank of the Ouvèze towards the rocky slopes below the castle. The dispossessed Count of Toulouse intervened militarily on several occasions between 1160 and 1251 to reconquer his lands and had the castle built and entrusted to a small garrison. An agreement between the bishops and the Count was reached in 1251, but the castle eventually returned to the Church in 1274 for lack of descendants.