The old town of Avigliana is one of the most significant in Piedmont, for its medieval architecture and its churches. The castle was probably built in 942 by the Marqueses Arduinici of Turin (it was probably Arduino the Hairless who built the first settlement of Castrum Avilianae) on the top of Mount Pezzulano. This castle was used by the Counts of Savoy at least from 1137. In 1691, after conquering it, the French Marshal Catinat got it definitively demolished, leaving the remains we can see after a pleasant walk from Piazza Conte Rosso.
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.