The site of Cuzorn, located in a bottleneck of the Lémance valley, allowed control of access to the region, but its origin remains unknown. The first mention of Cuzorn dates back to 1242, in the ruins of the Belleperche abbey, where an inscription mentions a certain B. de Cuzorn.
In 1259, the local nobility paid homage to the Count of Toulouse, including the brothers Gaubert, Pons, Guillaume, and Gaillard de Fumel, although neither lordship nor castle were mentioned at Cuzorn. However, documents from 1270 mention the lords of the castle of Cuzorn and Amalvinus de Cuzorn in conflict with the Bishop of Agen, suggesting a construction of the castle between 1260 and 1270.
Over the centuries, the lordship of Cuzorn had several owners, including the de Lézergues family and later the Gontaut de Saint-Geniès. In 1442, the castle was besieged, and later its defenses were dismantled. Subsequently, the lordship passed between different families until the 19th century.
In 1953, the castle was acquired by Georges Rastel, who undertook significant renovation work. In 1995, Thierry Delrieu became the owner of the castle, while the ruins were transferred to the municipality in 1996. In 1950, the castle was listed as a historical monument.
The Church of St Donatus name refers to Donatus of Zadar, who began construction on this church in the 9th century and ended it on the northeastern part of the Roman forum. It is the largest Pre-Romanesque building in Croatia.
The beginning of the building of the church was placed to the second half of the 8th century, and it is supposed to have been completed in the 9th century. The Zadar bishop and diplomat Donat (8th and 9th centuries) is credited with the building of the church. He led the representations of the Dalmatian cities to Constantinople and Charles the Great, which is why this church bears slight resemblance to Charlemagne's court chapels, especially the one in Aachen, and also to the Basilica of San Vitale in Ravenna. It belongs to the Pre-Romanesque architectural period.
The circular church, formerly domed, is 27 m high and is characterised by simplicity and technical primitivism.