The Porvoo Cathedral was originally made of wood. The first stone walls were built between 1410 and 1420 and in 1450 the church was expanded four meters towards east and six meters towards south.
The cathedral has been destroyed by fire numerous times; in 1508 by Danish and in 1571, 1590, and 1708 by Russian forces. On May 29, 2006, the outer roof collapsed after arson, however with the inner ceiling undamaged and the cathedral interiors intact. The Cathedral was reopened on 2 July 2008.
Porvoo Cathedral is situated in the middle of Porvoo well-preserved and beautiful old town, which is popular tourist attraction particurarly in summer season.
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.