The Kollegienkirche was built between 1694 and 1707 for the local Benedictine university founded in 1622. The university was disbanded in 1810 but reopened in 1962 as part of the University of Salzburg.
Certainly the largest and best Salzburg church designed by Erlach (who also built the Holy Trinity Church and renovated the Franciscan Church), the Collegiate Church is also one of the most celebrated Baroque churches in all of Austria.
The church is built on a modified Greek cross plan with a unique convex facade. Inside, the high altar by Anton Pfaffinger (1740) incorporates classical columns representing the Seven Pillars of Wisdom. Altar paintings are by Johann Michael Rottmayr.
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.