Wiltshire’s connexion with the Fitzalan earls of Arundel and their retainers suggest that he was related to his namesake, Sir John Wiltshire (d.1428/9), an intimate associate of Earl Thomas.
Meanwhile, during the Hilary term of 1402, Wiltshire had served as a juror in a suit in the King’s bench between Bishop Rede of Chichester and the prior of Hardham, with regard to alleged trespasses on the bishop’s warren at Coldwaltham, and had discharged office for at least one annual term as mayor of Arundel. In the court of the honour of Arundel held in December 1407, he was found to have been in breach of the regulations governing the sale of beer, and was fined accordingly. The precise duration of his service as bailiff of the manor of Arundel, for which post he was beholden to Earl Thomas, is not known (only his accounts for the year 1408-9 surviving). He was associated with Richard Wakehurst, a leading retainer of the earl, in 1411, as a co-feoffee of land at Slinfold, near Arundel; and it is of interest to note that he and Wakehurst were both returned to Henry V’s first Parliament (Wakehurst as a shire knight), very shortly after their lord the carl’s appointment as treasurer of the Exchequer. Wiltshire was described as a ‘webbe’ (weaver) on the parliamentary return, but no evidence of his trading concerns has survived. (However, John Wiltshire ‘the younger’ of Sussex, who may have been his son, is known to have had commercial dealings with a man from Dorset, whom he was suing for debt in 1416.)
Wiltshire attended the shire court at Chichester for the elections to the Parliaments of 1420, 1422 and 1429, being on each occasion one of a small group selected to witness the indentures of return for the county. Meanwhile, in 1426, in association with John Bartelot, junior, a prominent official on the late earl of Arundel’s estates, he had been enfeoffed of land at Broadwater. It seems likely that he was the John Wiltshire who in 1434 was listed among those of Sussex required to take the generally administered oath not to maintain anyone who broke the peace.
The John Wiltshire who attested the shire returns of 1447 and was living in Arundel in the 1450s was perhaps the MP’s son, although it would appear that he left as his heirs two daughters, one of whom married Thomas Bellingham†, the parliamentary burgess of that period.
