On 3 November 1920, Tolkien was demobilized and left the army, retaining his rank of lieutenant. His first civilian job after World War I was at the "Oxford English Dictionary", where he worked mainly on the history and etymology of words of Germanic origin beginning with the letter "W". In 1920, he took up a post as reader in English language at the University of Leeds, becoming the youngest professor there. While at Leeds, he produced "A Middle English Vocabulary" and a definitive edition of "Sir Gawain and the Green Knight" with E. V. Gordon; both became academic standard works for several decades. He translated "Sir Gawain", "Pearl", and "Sir Orfeo". In 1925, he returned to Oxford as Rawlinson and Bosworth Professor of Anglo-Saxon, with a fellowship at Pembroke College.