The St. Mary Magdalene's Church, dating from the middle of the 13th century, originally served as the parish church for the Hungarian citizens of the town (the Mátyás Church was for the use of the town’s German citizens). During the 14th and 15th centuries it was enlarged several times. During the first-half of the Turkish occupation it remained the only Christian church in the Castle; during the second-half it was converted into a mosque. Following the defeat of the Turks in 1686 it was given back to the Franciscan Order, who demolished most of the church except for the tower, and used the stones to build a new single-nave church, in the Baroque style. As a result of the damage sustained by the church during the 2nd World War, the nave was demolished and only the Gothic style tower was restored. The ruins behind the church have been used to form an exhibition of the history of the church. In 1792 Emperor Francis I, King of Hungary, was crowned in the church.
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.