Ragnar bade Aslaug, then called Krake, to sail away with him and be his wife, but at first she would not. “Herd-maidens wed not Kings,” she said, “Never can eagles mate with the ravens.”//
// Years later, after Ragnar and Aslaug had married and Aslaug had born four sons and two daughters, Ragnar was compelled to go a-viking in England. And for this his daughters had sewn him a banner upon which a raven with great wings was stitched. So, with the raven-banner flying over head, did Ragnar sail westward, to return no more.
[paraphrased from Asgard and Norse Heroes re-told by Katherine F. Boult]