The imposing Swabian castle of Rocca Imperiale is on the top of the hill over which the whole residential area extends. The fortress was ordered by Frederic II of Swabia in 1221, and he ordered the construction or refurbishment of 200 castles for defensive purposes in southern Italy. The castle was built in a place of great military and strategic importance and surveillance extended to the whole of the Gulf of Taranto. The development of the residential area followed the construction of the castle, bringing in the people from a series of fortified settlements in the area. Many feudatory lords alternated in the government of the area, constantly under barbarian attack, in the following 200 years.
In 1664, the castle withstood the attack of 4000 Saracen pirates who devastated Rocca, destroying the old 13th century church in the old centre of which only the lovely Romanesque bell tower with mullioned windows and cornices remains. In 1989, the last heirs of the family owning the castle decided to donate it to the Municipality of Rocca Imperiale.
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.