House of Cirksena

The Cirksena were a family of East Frisian chieftains who united most of East Frisia in the 15th century. In 1464 Ulrich Cirksena was made imperial count, and his descendants ruled the County, later Principality, of East Frisia until the line died out in 1744, when Prussia took over. Through marriage they also held the Westphalian county of Rietberg in the 16th and 17th centuries.