Ingolfssaga
From about 610 4A the Beor Clan had become a liability to the King of Torness. Quarrelsome, unruly and always ready to settle matters via unnecessary bloodshed, their control of Ostenmark was proving a royal headache. Seeking a solution to the problem, King Siglaf consulted his sages and heralds.
What he learned astonished him. Three generations earlier, a son of the Halgrimr Clan wed a Beoren woman. Through a series of misadventures, their son became the Jarl of Ostenmark, from whom the line descended; however, Volsungr tradition require descent from the male line. The Beoren claim to Ostenmark was therefore invalid -- it had rightfully claimed by the Halgrimr.
The Ingolfssaga is the account of the Halgrimr conquest of Ostenmark by Ingolf the Red, Prince of Torness, in 612. Composed by Ingolf's skald Munthrith Greeneyes, the Saga tells the story of the prince's canny handling -- and eventually banishing -- his Beoren foes, paying particular attention to the pivotal fight at the Battle of Bairn’s Cross. Originally written as a rhyming poem, it has recently been issued in prose form, to clear up inconsistencies.