Originally built in the Gothic style of the late 14th century, this complex of buildings was later reconstructed in Baroque style. From 1911 to 1913, it was rebuilt again and became a church. It is now the Parish church of the Holy Trinity, serving the population of Krašić, which is located near Jastrebarsko, about 50 km southwest of Zagreb. Enthusiastic visitors to the region will also not want to miss the nearby Pribić Castle, which is located just three kilometres east of Krašić, It is also fantastic.
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.