The oldest parts of Flen Church date from the 13th century. The choir was added in the 17th century, probably in 1664 and the new sacristy in 1746.
Baptismal font is the oldest item in Flen church, dating from the 12th century. There are also few other medieval artefacts, like crucifix from the 14th century. The pulpit was donated by Brita Ribbing-Rosenhane in 1664 and it was originally painted in black and white. The present appearance originates from the restoration made in 1966. The altar date from 1793 and organs from 1842.
References: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.