The records of the court of common pleas provide the earliest evidence for Moston. In Hilary term 1436, a suit that he, his wife Emma and two associates, John Lyttelbury and Thomas Hunt† of Bedford, had brought against Sir Thomas Waweton* in that court reached pleadings. According to them, the knight had unjustly detained two obligations, each for £100, entrusted to him for safe-keeping on 1 Mar. 1433, at which date Emma was the widowed Emma Blythe and had yet to marry Moston. By means of one of these securities, the plaintiffs had bound themselves to a couple of other burgesses, Thomas* and Ralph Bole*, from whom in turn they had received the other. The plea roll does not explain the circumstances of this transaction although it is likely that the securities were bonds exchanged prior to arbitration between the plaintiffs and the Boles. In response, Waweton declared that he was ready to surrender them to whomever the court directed, following which the justices summoned the Boles to Westminster, in case they wished to challenge the plaintiffs’ suit.
Another dispute to which Moston was a party went to arbitration a little later in the same decade. The resulting award, dated 10 Jan. 1438, provides the evidence for this quarrel, between the rector and parishioners of St. Peter de Merton, Bedford, on the one hand and Moston on the other. It arose from the latter’s acquisition of a garden, from which the parish claimed a rent of 8d. p.a. for the upkeep of the fabric of St. Peter’s. Moston had taken possession of the garden through a conveyance made to him by John Lyttelbury, his associate in the earlier quarrel, and John Blythe, evidently one of Emma’s in-laws from her previous marriage. The arbitrators were the masters of the local hospitals of St. John’s and St. Thomas’s. They ordered Moston and his wife to pay the rent in future, while directing the parishioners to say prayers for the couple (both during and after their lifetimes) and for the souls of Thomas Blythe and his wife, Agnes, every Sunday and on every fourth and sixth weekday. Again, Thomas and Agnes must have been former in-laws of Emma, although the exact relationship is unknown. Their inclusion in the prayers might suggest that the Blythes had possessed an interest in the garden in the past.
Far more significant than these minor disagreements was another quarrel in which Moston participated, for he was present when retainers of Reynold, Lord Grey of Ruthin, on the one hand and John Cornwall, Lord Fanhope, and his supporters on the other confronted each other at the Bedford sessions of the peace in January 1439. Moston came to the sessions as a member of Fanhope’s party. It is impossible to tell how active a role he played in the violence at the shire-house, but he felt it necessary to join others of Fanhope’s men in purchasing a joint royal pardon (in which he features as ‘of Bedford, yeoman’) in the following March.
While Fanhope was still alive, Moston did not play a significant role in the administration of Bedford, perhaps because he was still a relatively young man. He sat in his first known Parliament (alongside William Chichele alias Spicer*, one of Grey’s men at the fracas of 1439), before serving at least three terms as bailiff of the town. It is possible that he resided in London for part of the late 1440s. In Trinity term 1449, a few months before he took up his seat in the Parliament of 1449-50, a James Moston, ‘of London, yeoman’, stood surety in the common pleas for John Forstall, a taverner from Bedford.