In 1572, during the Eighty Year War with the Spaniards, Sea Beggars (Calvinist Dutch nobles) captured Brielle. After this work began on replacing the Medieval town walls with a modern fortress. This process of modernisation and replacement continued until 1713. The fortress ring has nine bastions and five ravelins and was designed by the fortress builders Willem Paen and Menno van Coehoorn. Since 1713 there have been few changes to the fortress, so the defences are some of the most important fortifications remaining in the Netherlands. It is possible to walk all the way around the walls to view them. Besides the walls there are also various buildings in the town centre which once had a military function, such as the Arsenaal, the Infirmerie and the Hoofdwacht (main guardhouse).
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.