Ragnars saga Loðbrókar

The Tale of Ragnar Lodbrok (Old Norse: Ragnars saga Loðbrókar) is an Icelandic legendary saga of the 13th century about the Viking ruler Ragnar Lodbrok. It is part of the manuscript of the Völsunga saga, which it immediately follows. The tale covers the origin of Aslaug, Ragnar's quest for the hand of Þóra Borgarhjǫrtr, his later marriage to Aslaug, the deeds of their sons (and Aslaug) in battle, and Ragnar's death at the hands of king Ælla of Northumbria.

The saga's sources include Adam of Bremen and Saxo Grammaticus, with whose Gesta Danorum (book IX) it overlaps in the description of Ragnar's pursuit of Thora, his marriage to Aslaug and the deeds of his sons. Ragnars saga is a sequel of sorts to the Völsunga saga, providing a link between the legendary figures of Sigurd and Brynhildr and the historical events of the ninth to eleventh century, as well as prestige to the Norwegian royal house by portraying Sigurd as its ancestor.

...
Wikipedia