Walter Devereux, 1st Earl of Essex
Walter Devereux was the eldest son of Sir Richard Devereux, who was created a Knight of the Bath on 20 February 1547 and died that same year, in the lifetime of his father, The 1st Viscount Hereford. Walter Devereux's mother was Lady Dorothy Hastings, daughter of The 1st Earl of Huntingdon and Anne Stafford, said to have been a mistress of Henry VIII. Through his paternal ancestry he was related to the Bourchier family, to which previous Earls of Essex had belonged: John Devereux, son of Walter Devereux who died at the Battle of Bosworth, married Cecily Bourchier, sister of Henry Bourchier, 2nd Earl of Essex.
William Devereux, Baron Devereux of Lyonshall
It was this ongoing warfare that led to a resumption of the Welsh Wars when Llywelin was declared a rebel on 12 November 1276. William Devereux was summoned for military service 12 December 1276 to May 1279 against the Welsh. It is probable that he was with Bohun as the earl initially suppressed the rebellion in Brecon, and then joined the main army for its advance into Wales in February 1277. On 2 July 1277 Devereux was summoned to muster at Worcester for military service against Llywelyn, Prince of Wales, and participated in the seizure of the harvest on Anglesey that summer. Following the Treaty of Aberconwy on 9 November 1277 hostilities lessened, but ongoing disturbances continued over the next few years as Edward I tried to extend English law and systems into Wales.