Tykocin Castle, then located on a border area in the Grand Duchy of Lithuania, was built in 1433 for Lithuanian noble Jonas Goštautas, voivode of Trakai and Vilnius, replacing the original wooden fortress. In the 1560s, upon the death of the last member of the Goštautas family the castle became the property of king Sigismund II Augustus, who expanded it. The construction was supervised by Hiob Bretfus, military engineer and royal architect. During the reign of Sigismund Augustus the structure served as a royal residence with an impressive treasury and library as well as the main arsenal of the crown. In 1611–1632 the castle was rebuilt again and surrounded with bastion fortifications by Krzysztof Wiesiołowski, starosta of Tykocin.
During the 1655 Deluge, the Radziwiłł army occupied the castle. On December 31, 1655, when the castle was besieged by troops of the Tyszowce Confederation, Janusz Radziwiłł, one of the most powerful people in the Polish–Lithuanian Commonwealth considered by some as the traitor, died here. Ultimately, the castle was captured on January 27, 1657.
In the following years the castle and surrounding lands were donated to Stefan Czarniecki in reward for his contribution in the war. The new owner rebuilt the castle after 1698. In November 1705 the meeting between the king Augustus II the Strong and Peter the Great took place here. During this meeting the Order of White Eagle was established by the King of Poland.
In 1734 the castle was destroyed by fire. Since that time, no inhabited building began to fall into disrepair. In 1771 remains of the castle were destroyed by flood and in 1914, during World War I, the material from the remaining walls was used by the German soldiers to build roads.
Based on the preserved plans of the fortress, found in the archives in Saint Petersburg, the residential part of the castle has been restored (west wing in the style of late Gothic). The original castle was built on a plan of a trapezoid with a courtyard and four cylindrical towers at the corners. The complex was surrounded with fortifications – curtains combined four terrestrial inner bastions.
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.