Zrin Castle was first mentioned in the 13th century as a fortress ruled by the Babonić clan. Between 1328 and 1347, it was possessed by the members of Iločki family. In 1347, King Louis I the Great bestowed the fortress to the noble Šubić family who then changed their family name after it, becoming the Zrinski. It remained in their possession until the Ottoman invasion and conquest of the region, which led to the fortress falling to them on 20 October 1577. It wasn't until 1718 that the castle was retaken from the Ottomans.
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.