Walter Devereux (1387–1419)
Walter Devereux assumed a position in the retinue of Henry IV following the death of his father on 25 July 1402 at the Battle of Pilleth. On 13 December 1402 Sir Edmund Mortimer declared his rebellion against Henry IV, but Devereux stayed loyal to the king. He was probably present at the Battle of Shrewsbury on 21 July 1403, and subsequently was knighted. Sir Walter Devereux was placed on a Commission of array for Herefordshire on 8 September 1403 to raise troops for the defense against the king’s enemies who have lately invaded the realm. It is probable that Devereux was present when Henry IV faced off with a combined Welsh and French force in South Wales during the summer of 1405, but no major battle occurred and the English force had dispersed by October of that year. Devereux remained an important supporter of the efforts to suppress the rebellion in Wales as Prince Henry assumed responsibility for the fight. Walter Devereux would be among 14 men below the rank of baron who would be retained for life by Prince Henry (the future Henry V).
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.