Kostianvirta battle was part of the Great Northern War (1700-1721). Russian army invaded to Finland in 1713 because the major Swedish army was fighting in central Europe. On October 1713, Finnish army under General Carl Gustaf Armfeldt had set the defence line to Kostianvirta river. When Russians attacked, Armfedlt’s 3,400 men first succesfully prevented 15,000 Russians to cross Kostianvirta.
On October 6, Russians made the landing coincidentally in Kostianvirta and near Mallasvesi and tried to besiege Finnish Army. Finnish soldiers were forced to withdrawn to the north. They lost 800 men and all nine cannons.
The monument of battle was erected in 1906. There are also reconstructed wooden trenches and remains of original defense structures.
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.