The history of the Haikko manor dates back to 1362 when a Dominican monastery owned the site. Jöns Olafsson Stenbock bought the manor and Haikko was a residence of Stenbock family for next 400 years. In 1871 it was bought by general Sebastian von Etter. Several members of the Russian Imperial family visited Haikko because von Etter was a close friend to czar Nicholas II. During the revolution in 1917 Grand Duke Kiril´s eldest son Wladimir was born and christened at Haikko. He was the nearest aspirant to the imperial crown of Russia and he became later the head of the Romanov family.
Current main building was built in 1913. The Vuoristo family purchased the manor in 1965. Today Haikko provides conference center, spa and hotel facilities.
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.