The Vehkalahti Church (today known as the St. Mary's Church) was built in the 14th century at the place were the town of Hamina is now. The history of Vehkalahti churches begins in 1396, when the first mention of town was written to a letter by Vyborg castle lord.
The present stone church was built probably between 1430 and 1470. Because of it's location near the Russian border it was robbed and burned twice in wars during the 16th century. Church burnt also 1821 in fire of Hamina and got brand new outfit by the famous architect Carl Ludvig Engel.
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.