Kwidzyn contains the partially ruined 14th century Brick Gothic Ordensburg castle of the Teutonic Order, namely the Bishops of Pomesania within the Order. Connected to the castle to the east is a large cathedral (built 1343-1384) containing the tombs of the bishops as well those of three Grand Masters of the Teutonic Knights.
The former Prussian fortress in Kwidzyn, which was occupied by the Teutonic Knights in 1233, received the city rights during the same year. In 1440 there was established the Prussian Union - today the Pomesanian"s cathedral chapter is the most precious historic and architectural treasures of Kwidzyn.
The wings of the castle with towers at the corners belonged to the defense system. Main tower today dominates the entire massif of the castle, which was also a bell tower lookout. The literally outstanding feature is a characteristic tower 'dansker' known as gdanisko of 1384. It was set by more than 50 meters from the west wing of the castle and the castle was combined with a long five spanning porches. Today the castle houses the Museum of the Castle. Kwidzyn history, its monuments and picturesque surroundings are enough attractions to visit for even the most demanding tourists.
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.