The abbey church of Sainte-Croix is, according to the tradition, the heir of a chapel built here by St. Helena in the 4th century and of an abbey founded by Charlemagne. Better documented is the creation of an Augustinian abbey by Algar, the new bishop of Coutances (formerly the prior of Bodmin Priory, Cornwall) in 1132. The Romanesque church was consecrated in 1202, being largely remade in the following centuries with successive renovations. The choir was remade in the 16th century while the bell tower is from 1860 to 1863.
During World War II, the bell tower (located laterally) collapsed and it was on its ruins where the body of Major Howie was placed; a new bell tower was rebuilt in 1957 on the forecourt in a modern style. On the church square stands the departmental monument in memory of the victims of the wars of Algeria and Indochina, opened in 2005.
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.