Members of the Bosom family are known to have lived in Bedfordshire from the mid 13th century onwards, if not before, and the subject of this biography was a direct descendant of the Alexander Bosom who, in 1276, acquired a sizeable estate in Stagsden from one of his kinsmen. The ownership of this particular property later gave rise to prolonged litigation between the MP and Walter Bosom, the then occupant, who managed to uphold his title in court; so it appears that the holdings built up by Alexander and his eldest son did not long remain intact. William’s share of this accumulation, which was left to him by his own father, comprised the manor of Roxton as well as various appurtenances in Chawston and Colesden, together worth an estimated £20 a year. Through his paternal grandmother, Alice Middleton, he also inherited a reversionary interest in part of the manor of Wotton, but this did not fall in until a few years before he died. From time to time Bosom consolidated his estates by purchase, acquiring blocs of land from local farmers as the opportunity arose, and it looks as if he already possessed a substantial amount of land in Wotton when Alice’s share of the manor finally came into his hands. As early as 1406, contemporaries were describing him as a resident of this part of Bedfordshire, and at some unknown date he bought outright an estate there which had belonged to the parson of Hatley in Cambridgeshire. On the marriage of his elder daughter, in 1422, he entailed it upon her husband, having already conveyed his other acquisitions in Roxton to a body of feoffees which included his parliamentary colleague, John Goldington II.
Bosom first appears in November 1389, when he stood bail for a local man who had been committed to Newgate gaol. No more is then heard of him until October 1395, the date of a Bedfordshire deed which bears his name on the list of witnesses. He may well have married his first wife, Joan, by then, since at some point over the next two years they became involved in a property dispute with one William Rysle, whom they and another couple arraigned at Bedford on an assize of novel disseisin. Not long afterwards, Bosom was instrumental in the endowment of Dunstable priory, acting with Richard Albion as a trustee for the settlement of a reversionary estate in the Luton and Dunstable area of Bedfordshire upon the house. Royal letters patent permitting the transfer of this property were issued to him and Albion in the spring of 1398, when he was also preoccupied with a lawsuit for the recovery of the manor of Stagsden, to which — as we have already seen — he advanced an unsuccessful claim as the lineal descendant of Alexander Bosom.
Comparatively little evidence has survived about Bosom’s more personal affairs. Like most gentlemen landowners he often acted as a feoffee-to-uses and witness for friends and neighbours, and several examples are still extant of his appointment to the trusteeship of estates in Bedfordshire, most notably those of Robert Mordaunt and
Thomas Pever
†. He also had dealings with the eminent judge, John Cockayne, with whom he shared a title to land in and around Carlton, almost certainly as a feoffee.