Church of St. Donat

The Church of St. Donatus stands on Zadar's Old Town peninsula, built directly on the ruins of the city's Roman forum. Construction began in the second half of the 8th century and is thought to have been completed in the 9th, commissioned by Donatus of Zadar, a bishop who led diplomatic missions to the Byzantine emperor and to Charlemagne's court. The church was originally dedicated to the Holy Trinity and only renamed after Donatus in the 15th century.

It is one of the few surviving examples of pre-Romanesque Carolingian church architecture in this part of Europe: a circular building around 27 meters high, with two concentric interior walls and three radiating apses, loosely comparable to Charlemagne's palace chapel in Aachen and to the Basilica of San Vitale in Ravenna. Because it was built on top of the forum, stone blocks, columns and other fragments from the Roman ruins were reused in its walls — some, including part of a Roman sacrificial altar, are still visible in the foundations today.

The building stopped functioning as a church long ago. Over the centuries it served as a warehouse under Venetian, Napoleonic and Austro-Hungarian rule, and briefly as an archaeological museum after Zadar became part of Yugoslavia. It has no roof and almost no interior decoration, but its unusual round shape gives it unusually good acoustics, which is why it is used today mainly as a concert venue — most notably for the summer Musical Evenings in St. Donatus festival of medieval and Renaissance music.

Because the church stands right next to Zadar Cathedral and the Roman forum, many visitors combine a day of sightseeing with a private gulet charter along the Croatia coast.