According to Alexander Myln's 16th century Vitae Dunkeldensis ecclesiae episcoporum ("Lives of the Bishops of Dunkeld"), when William was at Newbattle Abbey he authored a vita (that is, a biography) of John the Scot (died 1203), successively Bishop of Dunkeld and Bishop of St Andrews. The vita has failed to survive. William resigned his position as Abbot of Coupar Angus on 29 September 1258.
According to Alexander Myln's 16th-century work Vitae Dunkeldensis ecclesiae episcoporum ("Lives of the Bishops of Dunkeld"), when William was residing at Newbattle Abbey, he wrote a life story about John the Scot (died 1203), who later became Bishop of Dunkeld and Bishop of St Andrews. Regrettably, this biography has not survived to the present day. William stepped down as Abbot of Coupar Angus on September 29, 1258.