The Menwenicks took their name from the family seat in the parish of Trewen, some miles to the west of Launceston. They had longstanding associations with the borough of Dunheved, which one of their number, Roger, represented in Parliament in September 1397, and where another kinsman of the same name served as portreeve in 1431-2.
No details of William’s early training in the law have come to light, but his career was already well under way when he was admitted to Lincoln’s Inn in 1446-7.
It was about this time that the administration headed by Henry VI’s trusted minister, William de la Pole, earl of Suffolk, began to tighten its grip on the duchy, assisted by the minority of the heirs to two of the greatest estates in the county, those of the Arundells of Lanherne and Bodrugans of Bodrugan. There can be little doubt that Menwenick’s return to the controversial Parliament of 1447 for the duchy borough of Helston was officially sanctioned, and even at this date he may have been acquainted with one of the regime’s principal representatives in the far south-west, the courtier John Trevelyan, the duchy’s bailiff itinerant, whom he had succeeded in the escheatorship in 1443, and who sat in the Parliament of 1447 as a burgess for Huntingdon. Over time, their association was destined to grow closer. In the autumn of 1448 Trevelyan, now pricked sheriff of Cornwall, appointed William his receiver of writs in the King’s bench,
In parallel with his official appointments, Menwenick maintained a growing private practice. Before long, he could number among his clients the greatest of the Cornish gentry, the young John Arundell of Lanherne. In the summer of 1452 he was among the arbiters appointed to settle a dispute between Arundell and the earl of Devon’s cousin, Sir Hugh Courtenay* of Boconnoc;
Yet, even in Lostwithiel Menwenick did not enjoy universal popularity. By the spring of 1447 he was in dispute with the influential townsman, Robert Curteys†, who, so he claimed, had abducted his servant Christine Aleyn with the aid of a local tanner.
By this date Menwenick had established a further link with an important aristocratic patron. The de Vere earls of Oxford possessed Cornish interests by virtue of the marriage of Earl Richard (d.1417) to Alice, one of the daughters and coheirs of Sir Richard Cergeaux† of Colquite. In the autumn of 1452 Menwenick appeared in Chancery as part of a group of other men associated with Earl John, including John Paston* and John* and William Jenney*, in support of Oxford’s secretary and factotum, Thomas Denys, who was embroiled in an acrimonious dispute with Thomas Ingham* of Norwich, father of his wife’s first husband, and by early 1454 he was also being employed by the earl in other capacities.
There is good reason to suppose that Menwenick’s renewed election for the duchy borough of Launceston in 1459 owed much to wider political considerations. The Parliament would prove one of the most partisan of Henry VI’s reign and central to its proceedings was the attainder of the duke of York and his adherents, exiled in Ireland and Calais since their rout at Ludford Bridge, and the court thus had every reason to seek the return of its trusted supporters. Equally, however, it is possible that the electors of Launceston simply struggled to find affordable candidates: the wages of 6s. 8d. that Menwenick was paid hardly made a journey to Coventry seem worthwhile, even when augmented by an equally ‘generous’ reward of 3s. 4d., which he had to share with his colleague, Thomas Lymbery, and which was sweetened by an additional gift of wine.
Nevertheless, and in spite of his earlier connexions with John Trevelyan, Menwenick does not seem to have been regarded as a die-hard supporter of Henry VI’s rule, and following Edward IV’s accession in March 1461 he rapidly came to terms with the new regime. In spite of the execution for treason of one of his earlier patrons, the earl of Oxford, in February 1462, that July he was commissioned to hold an assession court of the duchy of Cornwall.
And as for the Corte of Tremeton, y have mycche laburr ther; but yette y have notte geffe no ple ther, for [Fortescue] ys asoynyd ij tymys a rewe yn his oune pleynte. And that sawe y never yn no place but ther: but that ys Menwynnycke, a felow of Corte of his, ys doyng, the whycche ys Steward ther.
Stonor Letters, i. 78.
Throughout these years Menwenick maintained a busy private practice, serving the greater gentry of his county as a witness, arbiter, or feoffee. Among his clients were the wealthy Henry Bodrugan†, Edward Courtenay of Boconnoc (the future earl of Devon), members of the Reskymer and Vivian families and the lawyer John Glyn†, and also some of the urban communities of the region, like the townsmen of Liskeard who in 1467 rewarded his services with a gift of wine.
Conversely, however, when Edward IV returned to the throne in the spring of 1471, Menwenick did not apparently face any consequences for his association with the Lancastrian regime. He continued as a member of the quorum of the Cornish bench, and by 1473 was once more being appointed as a justice to deliver the county gaol at Launceston of offenders,
