Although no definite evidence of his parentage has been discovered, it is probable that the William Mayhew who represented Dunheved in the Parliament of 1455 was the son of John Mayhew, who had sat in the Parliament of May 1413 for the same constituency.
Undoubtedly through the intervention of his putative father, who had long been associated with the influential duchy of Cornwall feodary John Hawley*, William also entered the latter’s service, and it was in this capacity that in June 1434 he seized a selection of pewter and silver vessels worth four marks as the goods of an outlaw, Richard Pluk of St. Neots. Although Pluk did not deny his outlawry, he challenged its validity on a technicality and demanded damages of £10.
Around this time Mayhew attached himself to Thomas Courtenay, earl of Devon. Increasingly irritated at being denied what he regarded as his rightful position of pre-eminence in the south-west by a regime which favoured to his regional rivals, the earl of Wiltshire and William, Lord Bonville*, in the autumn of 1451 Courtenay rallied his retainers, Mayhew among them, to proceed against his opponents with armed might. Having failed to achieve any significant success, the following spring he led his men east to join forces with those of the discontented duke of York, but the uprising came to a sudden and dramatic end with the arrest of the two lords at Blackheath. Mayhew, who was indicted for his part in the uprising, swiftly availed himself of the general pardon offered by the King.
It is not certain whether William’s association with the Courtenays of Tiverton and his family’s long service to the Lancastrian dynasty prompted him to throw in his lot with Henry VI in the dramatic final months of the reign. If Mayhew retained his Lancastrian loyalties beyond Edward IV’s accession, he did not live long enough to be placed at a disadvantage by these leanings, for he was certainly dead by the spring of 1462 when his widow, Alice, who was entrusted with the execution of his will, took possession of property in Launceston.
