Castle of the Masovian Dukes in Ciechanów was built on the turning point of the fourteenth and fifteenth century by Prince Janusz I (1379-1429). The towers located in the four corners of the castle's square formation help to defend the stronghold, and additional 10 metre high defensive walls. Due to dozens of reconstructions and expansions of the castle, the militaristic stronghold transformed into a royal residence. In the fifteenth century, the castle was raised by an additional level and a raised courtyard.
In 1547, the stronghold changed its function into a aristocratic residence. It was the last period of the stronghold's glory. After the Third Partition of Poland, the stronghold became part of Prussia, and was partially deconstructed for cheap building material. In 1818, the castle was owned by the House of Krasiński, in the twentieth century the castle was fully rebuilt.
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.