Sant'Orsola Church was built for the 'Compagnia di Sant'Orsola' (Brotherhood of Saint Ursula), a group of believers which was founded in 1564 in the neighbouring church of Santi Quaranta Martiri Pisani al Casalotto.
The church was open to the public in 1662. The nave, and maybe the entire building, was designed by Giacomo Amato. In 1672 a beautification work started. During this period the building was decorated with stuccos and paintings. In the following century another beautification work was made. As a result of these actions, the church houses several artworks of important Sicilian artists.
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.