Hrólfs saga Gautrekssonar
Gautrekr was a Geatish king who descended from Odin himself. He lost his wife Alfhild and went somewhat out of his mind, ignored all matters of state, and spent all his time on Alfhild's burial mound, flying his hawk.
He had two sons Ketill and Hrólfr Gautreksson, and Ketill became a great Viking who inherited his father's kingdom.
In Uppsala ruled Erik, the king of Sweden, who had only had one child, Þornbjörg, born a daughter. He was a transmasculine king who would rather fight and partake in masculine activities then participate in traditionally feminine undertakings. He also preferred to be called Thorberg, a male name, and insisted on using male pronouns. He was called Þórbergr konungr, king Thorberg. Thorberg's father gave him the royal estate of Ulleråker, where he kept a retinue of housecarls.
Ketill suggested that Hrólfr make a try to woo the king and after much hesitation, Hrólfr agreed. His brother said that "it would be the most noble marriage in the Northlands to have the son of the king at Uppsala for husband" and "many have little courage in a big body and it is a shame that you who are a man durst not speak to menfolk".
Hrólfr summoned his courage and went to Ulleråker with his fosterbrother Ingjald of Denmark and sixty well-armed warriors to woo Thorberg.
Þórbergr was sitting on the throne, dressed in armor. When Hrólfr proposed, he rushed up, grabbed his weapons and ordered his men to "fetch and bind the fool who offended king Þórbergr". Hrólfr put on his helmet and asked his housecarls to leave and then he manfully slew no less than twelve of Þórbergr's champions before he had to flee the overwhelming foe. Everybody in his company returned to Geatland alive.
After a Viking campaign in the West to both Scotland and Brittany, Hrólfr steered his fleet of six ships and a selected crew northwards and did not stop until he reached Uppsala. When the new peace agreement between Hrólfr and king Erik had been established, Hrólf went to Ulleråker to propose once more to the Þórbergr.
Þórbergr screamed that he'd become a shepherd in Geatland before he had any power over him. After a hard fight Þórbergr was captured and not long afterwards he married Hrólfr.
After some time Hrólfr succeeded his brother Ketill as the king of the Geats, but that story was not recorded.