Lagertha (also Ladgerda, Ladgertha) was, according to the 12th century accounts of Saxo Grammaticus, a Norse shieldmaiden, local ruler (jarl) in Norway and first wife of the Danish Viking hero Ragnar Lothbrok, who is said to have lived in the 9th century.
There is no direct evidence of her historical existence. Some authors associate her with the goddess Thorgerd (Þorgerðr Hölgabrúðr) or the Valkyries.
According to estimations of Nora Kershaw Chadwick the name Lagertha used by Saxo is a latinization of the old Norse name Hlaðgerðr (Hladgerd). This can be traced back to the word elements hlaða, "weave" or hlað, "lacework, headdress" and garðr, "protection" (compare etymology of the word garden).
This is not to be confused with the similar Frankish or Old High German name Luitgard or Liutgard, in which only the second word element gard has the same meaning, while liut stands for "people," "members of a people."
In other languages like English there are also deviating spellings like Lagertha, Ladgertha or Ladgerda.
The ninth book of the Gesta Danorum (9, 4, 1 - 9, 4, 11) of Saxo Grammaticus is the only medieval text in which Lagertha is reported.
Saxo presents Lagertha as a woman experienced in war and first wife of the Danish king Ragnar Lothbrok, with whom she has three children. Lagertha's most striking features are her extraordinary martial skills, despite her delicate limbs, and her magnificent long hair.
Her residence is in the Gaula Valley (Gølerdal) area of Norway.
Lagertha enters the limelight of history in Saxo at the time when the Swedish king Frø (Frö, Old Norse Freyr) invades Norway, slays the local king Sywardus, and sends the women from his court to a brothel to force them into prostitution.
The slain Norwegian king's grandson, Ragnar, then moves to Norway with a force to avenge Sywardus. Many of the humiliated court women do not resign themselves to their fate, but gather armed and in men's clothing to fight back, thus helping Ragnar to his victory over Frö, who falls in battle.
Lagertha, who fights in the first line, stands out among the fighters as particularly brave. According to Saxo, she is already a woman experienced in war.
Ragnar falls in love with the young warrior woman, whom he recognizes as such by her long hair and about whom he learns that she comes from a noble Norwegian family.
He confesses that he owes his victory to her. He asks for her hand, whereupon she informs him via messengers that she is expecting him in her palace. Ragnar travels to her by ship, but there two wild animals she has sent are waiting for him: a bear and a dog.
Ragnar slays the two beasts, so that Lagertha finally agrees to the marriage. The marriage produces two daughters, whose names are not known, and a son named Fridlevus (Fridlew).
Ragnar leaves Lagertha after falling in love with Thora, the daughter of King Herothus. He defeats two huge poisonous snakes that the king has recklessly raised, and then takes Thora as his wife.
Lagertha also marries again, but obviously not a happy marriage. When her former husband Ragnar and his crew are harassed by the Jutes and Scania under their king Harald, he asks his outcast wife for support.
Since her "first love [...] still fills her heart to overflowing", she indeed rushes to his aid with her new husband, her son and 120 ships.
Again it is Lagertha who helps Ragnar to victory by her fighting skills, so that Harald takes flight. After her return home Lagertha stabs her second husband, so that she can now rule her kingdom alone. Saxo writes about this according to Paul Herrmann's translation (9, 4, 11, 4): "The defiant sense of the woman did not want to share the kingdom with her husband, but to rule without a husband."
Saxo's account of Lagertha's life ends here. About her further life and her death we learn nothing. Lagertha's second husband is not mentioned by name, and the marriage of the two does not appear in the report.
Based on Saxo's Gesta Danorum, Christen Pram wrote a historical play entitled Lagertha (1789). This in turn was the model for the ballet Lagertha (1801) by Vincenzo Galeotti (choreography) and Claus Schall (music), which as a synthesis of the arts includes songs, pantomime, dance and dialogues. The performance at the Kongelige Teater in Copenhagen under director Galeotti was well attended.
In the Canadian-Irish television series Vikings, Katheryn Winnick plays a shieldmaiden Lagertha as one of the leads, based in part on Saxo's portrayals. Here, too, her husband Ragnar Lothbrok enters into a new relationship, but his new wife is not Thora but Aslaug, who does not appear in Saxo but does appear in Ragnar's saga. Lagertha here stabs her third husband to death after he did not accompany her on her campaign to support Ragnar and publicly humiliated her after her return.