At the beginning of the Kalmar Union age Sandemar was owned by the Teutonic Order of Livonia. Erik Axelsson Tott bought all the Order's property in Sweden in 1467. During the 1500s the ownership was unknown. In the 1600s the Sandemar belonged to families Oxenstierna, Bonde and Falkenberg. The Royal Council and president Gabriel Falkenberg completed the present main building around the year 1693. Sandemar is today privately owned by Karin Mattson Nordin, daughter of the real estate developer John Mattson.
The main building of Sandemar is made of wood, covered with tiles and the water side plates to protect against sea winds. The farm escaped the Russian ravages in 1719, probably through the deterrent effect of the nearby Dalarö Fortress had, and have therefore preserved the Carolinian period decorations. The English garden is added later with greenhouse, vegetable and fruit tree plantations.
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.