St. Nicholas' Fortress was built on the left side at the entrance to St. Anthony Channel, on the island called Ljuljevac. The island is situated at the entrance to the Šibenik channel across the Jadrija beach lighthouse. St. Nicholas' Fortress got its name from the Benedictine Monastery of St. Nicholas, which was originally on the island, but due to the construction of the fortress, it had to be demolished. At the request of domestic Croat population of Šibenik, the Venetian captain Alojzije de Canal decided to build a fort on the island of Ljuljevac in 1525. The fortress was designed and built by the famous Venetian architect and builder Hyeronimus di San Michaela. It was built by in the 16th century to prevent Turkish boats from reaching the port. St. Nicholas' Fortress was armed with 32 cannons. However, its imposing appearance and size were a bigger threat to the enemy than cannons ever were.
The fortress is one of the most valuable and best preserved examples of defense architecture in Dalmatia. It is made of brick because that material was considered to be most resistant to cannonballs, while the foundations are made of stone. Although defense capabilities of the fortress have never been tested in military operations, the structure still proved successful in protecting the city from sea-bound enemy attacks. During the centuries of use, the structure served to various armies and has undergone a number of renovations, some of them necessary only because of the development of arms. It was completely abandoned by the military in 1979 and has been undergoing renovation ever since.
St. Nicholas' Fortress was included in UNESCO's World Heritage Site list as part of 'Venetian Works of Defence between 15th and 17th centuries' in 2017. After reconstruction work that lasted for two years, the fortress was open to visitors in July 2019.
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.