About Þrándr Nórrasson, king of Trondheim
Thránd ruled Trondheim (Þrándheimr) which was named after him and refers approximately to present day county of Sør-Trøndelag and the southern parts of Nord-Trøndelag, rather than to the city now called Trondheim.
Hversu Noregr byggdist ('How Norway was Settled') says he was a son of Nórr, legendary founder of Norway.
Eireks saga víðförla ('The Saga of Eirek the Traveller') also brings in Thrand as the first king to reign in Trondheim. Thrand's ancestry is not given here, but he is the father of Eirek the Traveller (Eirekr inn víðfǫrli) the hero of the saga.
Hálfdanar saga Eysteinssonar ('Saga of Halfdan Eystein's son', early 14th century) states instead that Trondheim was named from King Thránd, the father of Eirek the Traveller, but also states that Thrand was son of King Sæmingr of Hálogaland, son of Odin, and that Thránd's mother and Sæmingr's wife was Nauma after whom Naumu Dale was named. For more on Sæmingr see Sons of Odin. Thrand's wife is here said to be Dagmær sister of Svanhvít the wife of Hrómund Grip's son, the protagonist of Hrómundar saga Gripssonar. The saga says that Eystein, son of Thrand and Dagmær, married Ása, a daughter of Sigurd Hart (the maternal grandfather of Harald Fairhair), and she bore him Halfdan, the hero of the saga. This places Thrand just three generations back from Harald Fairhair. But this saga seems to be a late and untraditional creation, dating only to the early 14th century.