Estrid

The House of Estridsen supplied Denmark's kings from 1047 to 1412 and three rulers to Sweden and one to Norway. It takes its name from Estrid Svendsdatter, daughter of Sweyn Forkbeard and sister of Cnut the Great, whose marriage to the earl Ulf Jarl founded it.

Their son Sweyn Estridsson, born around 1019, took the Danish throne in 1047 and fathered over twenty children, five of them kings, among them Saint Canute. His descendants kept the Danish crown for three centuries, and the family arms became those of Denmark.

In 1337 the house had ruled Denmark for nearly three centuries; Valdemar IV soon revived its fortunes. His youngest daughter Margaret I, born in 1353, became queen regnant of Denmark, Norway and Sweden and founded the Kalmar Union, joining the Scandinavian crowns for more than a century. On her death in 1412 the line ended and the crown passed to her grandnephew Eric of Pomerania; all later Danish monarchs remained its cognatic descendants.