|House of Estridsen|
|Parent house||House of Knýtlinga (maternal)|
House of Munsö (hypothetical 18th century theory)
|Country||Denmark, Norway and Sweden|
|Founder||Sweyn II of Denmark|
|Current head||Extinct, last monarch of this House was Margaret I (r. 1387–1412)|
Knud Mogensen Løvenbalk (last known agnatic member of the family, died after June 1598)
|Titles||King of Denmark,|
Queen of Norway,
Queen of Sweden,
King of Sweden,
Duke of Schleswig,
Count of Flanders,
Duke of Gothenland
|Cadet branches||Abelslægten line (extinct 1375)|
Løvenbalk line (extinct after June 1598)
The House of Estridsen was a dynasty that provided the kings of Denmark from 1047 to 1412. The dynasty is named after its ancestor Estrid Svendsdatter. The dynasty is sometimes called the Ulfinger, after Estrid's husband, Ulf the Earl. The dynasty also provided three of the rulers of Sweden in the years 1125–1412. Their family coat of arms became the coat of arms of Denmark and therefore influenced the coat of arms of Tallinn and the coat of arms of Estonia.
The Royal Court of Denmark does not differentiate between different royal houses among the early Danish kings, but uses the term "the descent of Gorm the Old" about all the pre-Oldenburg monarchs.
The name of the Estridsen dynasty recalls their acquisition of the Danish crown through the marriage of Ulf the Earl to Estrid Svendsdatter of the House of Knýtlinga, daughter of Sweyn Forkbeard and sister of Cnut the Great. Later genealogies (introduced by the Danish historian Jakob Langebek in the 18th century) trace the family from Jomsviking leader Styrbjörn the Strong, a scion of the Swedish royal family, who in turn is given a descent from legendary King Sigurd Hring, regarded as mythical by most modern historians (no actual sources mention such an ancestry). Reliable ancestry traces back no earlier than Ulf's own father, the obscure Thorgil Sprakling and grandfather Björn (in sources called Ursius), the latter thus alternatively being identified as the above Styrbjörn by Langebek.
The dynasty reached its peak with the Kalmar Union, when its members reigned as kings of Denmark, Norway and Sweden in personal union. The dynasty came to end in 1412 with the death of its last member Queen Margaret I. All of the subsequent monarchs of Denmarks are cognatic descendants of the House of Estridsen.
Sweyn died at the royal estate Søderup in [the Duchy of] Schleswig April 28, 1076 (the Danish annals have, certainly incorrect, 1074) and was buried in Roskilde Cathedral. [S. døde paa Kongsgaarden i Søderup i Slesvig 28. April 1076 (de danske Aarbøger have, sikkert urigtig, 1074) og blev begravet i Roskilde Domkirke.]
At Vilhelm er død før Kongen, meddeles af de ikke meget senere Skribenter Anonymus Roskild. (Lgb.I. S. 378) og Ætnothus (Lgb.III. S. 338). At fremdeles Svend Estridsen døde 1076 og ikke allerede 1074, er ligeledes hævet over enhver Tvivl; naar nu ikke destomindre en hel Række Kildeskrifter lader ham dø allerede 1074, saa synes dette at hænge sammen med det allerede tidlig opstaaede og hos Saxo opbevarede Sagn om, at Vilhelm døde faa Dage efter Kongen og af Sorg over hans Død. Det kan da tænkes , at man har draget Kongens Død tilbage til Bispens Dødsaar 1074, ligesom Nyere (t. Ex. Molbech, hist. Aarb. III S. 19) drage Bispens Dødsaar frem til 1076 for at faa Begges Dødsaar til at falde sammen." ... & ... "men derimod giver en ny Skrivelse, som Paven afsendte til Svend d. 17. April s. A. , En det bestemte Indtryk, at der i Mellemtiden er foregaaet Noget, hvorved Svend har gjort sig Paven forbunden