The name "Ofstad" or "af Awaldzstadom" comes from Augvald (Old Norse: Ogvaldr) was a semi-legendary Norwegian petty king portrayed in the legendary Norse sagas. If considered historical, reconstructed estimates based on saga information would have Augvald living some time in the 7th century AD. His kingdom was said to have been based in Jøsursheid, somewhere in the interior of south-western Norway. After a number of naval battles he succeeded in conquering the islands off the western coast of Rogaland. He subsequently moved his kingdom's seat to the north-east of Karmøy, the largest of those islands and adjacent to the strategically important Karmsund strait, to a site later given the name Avaldsnes, after the king. Augvald's kingdom further expanded to incorporate parts of what is today south-western Hordaland.
Augvald had several daughters, including two who notably fought alongside him as so-called shield-maidens, or female warriors. He owned and worshipped a sacred cow, which he always kept with him, believing he owed his victories to the cow and the power of its milk. Augvald was killed during a battle with his rival Ferking, the native king of western Karmøy, with whom his story is interlinked.
Norse sagas telling parts of the story of Augvald include the (both by Snorri Sturluson in Heimskringla and by Oddr Snorrason), the Saga of Half & His Heroes and the Flateyjarbok. He also appears in the later Historia rerum Norvegicarum and other works of the Icelandic historian Thormodus Torfæus, who lived and worked in Kopervik, Karmøy. In addition, Augvald is mentioned in the Avaldsnes parish register, and in local Karmøy legends. Scholars have been very sceptical about the reliability of the legendary sagas, which were dismissed as being of little value even in the early 20th century, before the establishment of general source criticism. The legendary sagas' value as sources has not been re-evaluated in recent times.