The Abbey of Saint-Gildas is dedicated to St. Gildas (c. 500–570) who was a British historian and cleric. He is one of the best-documented figures of the Christian church in the British Isles during this period. According a legend Gildas established the abbey, but there are no written evidences. Buildings were destroyed by Norman raids in the 10th century.
The first known record dates from 1008 when the abbey was restored by the order of Geoffrey I of Bretagne. The new inauguration was held in 1032. The heyday of Saint-Gildas Abbey was in the 11th-14th centuries. During the Hundred Years' War most of the archives were destroyed. The monastery started to decay in the 16th century. The nave of the church collapsed in 1668 when a lightning hit it.
the next restoration took place in the late 1600s. The abbey church was moved as a parish church during the Great Revolution in 1796.
References: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.