According to later inscription (presumably from 17th century), St. Giles Church was founded in 1082 by Władysław I Herman as thanks for birth of his son Bolesław III Wrymouth. Actually it was founded probably not later than in 1138 by Hemran's son, Bolesław III Wrymouth. The church was restored between 1924 and 1926 and thoroughly between 1936 and 1938 with raising of the tower by one storey. The restorations changed the architecture of the church.
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.