The Penarth family were established in the Cornish parish of Morval by the early fourteenth century. No details of Thomas’s early life or parentage have been discovered, but it is probable that he was a kinsman of Richard Penarth, who in 1435 held lands in Pennarth and Morval from John Bate*, property which in 1451 was said to be worth 40s. p.a.
By the end of the 1440s Penarth had formed an association with the influential courtier John Trevelyan, a connexion which was to be of some importance to the course of his subsequent career, and which most likely was instrumental in seeing him returned to the Commons to the two turbulent Parliaments which assembled in the course of 1449. Both assemblies met as the military situation in Normandy became increasingly desperate, the second, indeed, just four days before Charles VII’s triumphal entry into the duchy’s capital of Rouen. It was not hard to predict that the Commons would be restive, and the court did its best to ensure the return of its supporters wherever it could. Trevelyan himself held the shrievalty of Cornwall, and while this precluded him from sitting in the Commons himself, it did give him a degree of influence over the choice of the representatives of the county’s smaller boroughs. Trevelyan also entrusted Penarth with various personal errands at Westminster: in late June he named him as one of his sureties for an Exchequer grant (probably an appointment made in absentiam, since the Commons were at the time gathered at Winchester),
Trevelyan might well make an effort, for the autumn Parliament saw a concerted attack on the King’s chief minister, William de la Pole, duke of Suffolk, and the members of the court circle who – like Trevelyan – were perceived to have enriched themselves at the Crown’s (and by, inference, the commonalty’s) expense. Not even the presence of a substantial contingent of retainers like Penarth in the Commons could prevent the duke’s impeachment and the passage of an Act of Resumption which cost Trevelyan, among others, many of his Crown grants and offices. Like other victims of the Commons’ wrath he was, however, quick to recover a large proportion of his posts, and not long after being restored to the constabulary of Trematon castle in October 1452 he appointed Penarth as his deputy.
With Edward IV’s accession in March 1461, Penarth’s lieutenancy of Trematon came to an abrupt end. Like other members of Henry VI’s household Trevelyan (and by implication Penarth) lost their offices and were replaced by the new rulers’ trusted servants. In common with many other former Lancastrian officials, Penarth now withdrew into private life. He played no further part in local government, other than periodically serving as a juror, and from time to time is found attesting the property transactions of some of the more important men of Cornwall, including Henry Bodrugan† and his Morval neighbour John Glyn†.
If Penarth’s earlier links with the earl of Warwick’s retainer John Nanfan held out a hope of a return to public office, this was dashed by Nanfan’s death in the first years of Edward IV’s reign. Moreover, he was now drawn into an acrimonious quarrel between a group of his distant kinsmen, Robert*, William* and Thomas Trethewy†, and one Edward Hydon, who accused him, once again, of robbery.
