William’s brother John died leaving William as the heir.
4/5/1351, William age 21 at the death of his father inheriting the manor of Compton Monceux.
6/12/1353, Inquisition by the escheator of Berkshire: John de Fyenles held in chief of Queen Philippa in his demesne as of fee on the day of his death the bailiwick of the forestership of Twychene and Cotham in Berkshire by service of 10s to be paid yearly at Windsor castle and other lands. William is his son and heir. … Order to cause William son of John de Fyenles to have seisin of the bailiwick of the forestership of Twychene … the king has taken William’s fealty. (S) CCRs.