Santa Clara Monastery was founded by Don Sancho Sanchez de Velasco and his wife Doña Sancha García in 1313. Throughout the centuries almost all members of the Velasco family were buried there.
The Gothic church has a single nave and is divided into side chapels. The High Altar has three altarpieces bathed in gold in the Rococo style.
The museum shows the works of art and relics of the monastery, most donated by the family Fernandez de Velasco.
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.