The so-called Piasts' Castle in Gliwice dates back to the mid-14th century. It consists of a tower from 1322, which was originally part of the city walls, and an adjoining building which was probably an armory. Modifications were carried out in the 15th century, between 1558-61 it became the residence of Friedrich von Zettritz. Later it was an armory, a jail, a magazine and since 1945 a museum. Between 1956-59 it was thoroughly rebuilt and partially reconstructed. Since that time it is claimed to be a Piast castle, although no sourced evidence backs this claim. Since 1959 the castle has been part of the Gliwice Museum.
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.