Thyra Haraldsdatter Queen of Norway
- Born: Abt 940, Denmark
- Marriage (1): Styrbjörn Starke Olafsson Viking of Sweden
- Marriage (2): King Boleslav I Chrobry 'the Brave' Poland of Poland
- Marriage (3): King Olav I Trygvesson Of Norway about 998
- Died: 24 Sep 1000, Norway about age 60
Thyra Haraldsdatter was Eric & Evan Obrock's 31st great-grandmother. Her brother, King Sweyn I "Forkbeard", was 30th great-grandfather of Eric & Evan, through different descendants.
It has been suggested that Olaf I's ambition was to rule a united Christian Scandinavia, and we know that he made overtures of marriage to Sigrid the Haughty, queen of Sweden, but negotiations fell through owing to her obstinate heathenism. He instead made an enemy of her, and did not hesitate to involve himself in a quarrel with King Sweyn I of Denmark by marrying his sister Thyra, who had fled from her heathen husband Boleslav in defiance of her brother's authority.
Both his Wendish and his Irish wife had brought Olaf wealth and good fortune, but Thyra was his undoing, for it was on an expedition undertaken in the year 1000 to wrest her lands from Boleslav that he was waylaid off the island Svold, near Rügen, by the combined Swedish, Danish and Wendish fleets, together with the ships of Earl Håkon's sons. The Battle of Swold ended in the annihilation of the Norwegians. Olaf fought to the last on his great vessel the "Long Serpent" (Ormurin Langi), the mightiest ship in the North, and finally leapt overboard and was seen no more.
Thyra married Styrbjörn Starke Olafsson Viking of Sweden, son of Olaf II Björnsson King of Uppsala and Unknown. (Styrbjörn Starke Olafsson Viking of Sweden was born about 903 in Sweden and died in 986 in Fyrisval, Uppsala, Sweden.)
Thyra next married King Boleslav I Chrobry 'the Brave' Poland of Poland, son of Mieszko I Prince Of Poland and Dúbravka von Böhmen Princess of Bohemia. (King Boleslav I Chrobry 'the Brave' Poland of Poland was born about 966 in Poznañ, Poznañ, Poland, died on 23 Jun 1025 and was buried in 1025 in Cathedral Basilica of St. Peter and St. Paul, Poznan, Poland.)
Thyra next married King Olav I Trygvesson Of Norway, son of Trygve Olafsson small king in Norway and Astrid Eiriksdatter, about 998. (King Olav I Trygvesson Of Norway was born about 963 and died on 9 Sep 1000.)