Vieste Co-Cathedral was built in Apulian Romanesque style as a cathedral in the 11th century. It has been altered due earthquakes and Saracen attacks and was rebuilt in second half of the 18th century in Baroque style.
It is dedicated to the Assumption of Mary. It has a basilica plan with a nave and two aisles. Its bell tower was rebuilt in Baroque style in the 18th century after the previous one collapsed. It became a minor basilica by papal decree of 12 February 1981.
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.