"Egil's Saga" is an Icelandic saga written in Old Norse in 1220–40, which recounts a battle at "Vínheidi" (Vin-heath) by "Vínuskóga" (Vin-wood); it is generally accepted that this refers to the Battle of Brunanburh. Egil's Saga contains information not found in other sources, such as military engagements prior to the battle, Æthelstan's use of Viking mercenaries, the topology of the battlefield, the position of Anlaf's and Æthelstan's headquarters, and the tactics and unfolding of events during the battle. Historians such as Sarah Foot argue that Egil's Saga may contain elements of truth but is not a historically reliable narrative.