The Belasyses, long established in county Durham and Yorkshire, were of little account until after the Reformation, when they acquired Newborough and a 5,000 acre estate to the south-east of Thirsk. Belasyse’s father was the first MP in the family, being returned for Thirsk in 1586, and Thomas himself sat for the borough in 1597. In February 1601 Belasyse was prosecuted for having been married by a Catholic priest, which perhaps explains his failure to be returned at the next two elections, even that of 1604, when his father was sheriff of Yorkshire. While his younger son, John, later claimed that he had ‘newly converted to the Catholic faith’ in 1615, this seems unlikely, as he was returned for Thirsk once again in 1614; he left no trace upon the records of the session.
Re-elected for Thirsk in 1621, Belasyse moved for his brother-in-law Sir Richard Cholmley* to be allowed parliamentary privilege (2 Mar.) and, as a wool producer, he opposed Sir Thomas Wentworth’s* attempt to continue the exemption of the Halifax clothiers from the 1555 Wool Act, on the grounds that the statute had ‘grown out of use’ (5 March). He had, however, signed Wentworth’s return as knight of the shire, and on 23 Mar. it was presumably in the latter’s interest that he moved to consider the punishment of the high constables who had become scapegoats for the dubious practices employed during the election. He was named to a single committee, to renew the 1610 Act concerning moor burning in the north (26 May).
Belasyse was returned once more for Thirsk in 1624, when he played a more active role in the central debate about a breach with Spain. At the end of the debate of 1 Mar. about whether to end negotiations for a Spanish Match, he considered ‘that it is sufficiently disputed of and that more consultation is needless’, agreeing with Sir Robert Phelips’s motion to confer with the Lords about a joint statement. However, he clearly harboured doubts about the potential cost of a war. Four days later, when Sir Edwin Sandys tabled a declaration promising to finance any conflict arising from a breach with Spain, Belasyse warned that it was ‘not fit to think of a war before we know what kind of war’. In the subsidy debate of 19 Mar., angered by proposals from the lawyers Sir John Walter and John Glanville for a grant of four subsidies, he reminded the House that ‘subsidies come in not as easily as fees; that two, that spoke before, did soar [to] too high a pitch’. Urging ‘care of the poorer sort and how it may be had’, he proposed a mere two subsidies.
Besides the question of war finance, Belasyse was generally more active in the Commons in 1624 than he had been in his previous parliaments. At the second reading of the bill for sheriffs’ accounts on 8 Mar., he called for examination of patents for old debts, and moved for sheriffs’ liability to be limited to seven years, explaining, perhaps with reference to his father, ‘that he knoweth one that was sheriff above twenty years since was lately troubled (his under-sheriff being dead), notwithstanding his quietus est, for some things concerning his shrievalty’. On 27 Apr., when Sir Thomas Savile named lord president Scrope as a recusant officeholder, Belasyse, related to Scrope through his mother, insisted ‘that within these two years, Lord Scrope and all his family received [communion]’. On 3 Apr. he tabled a fresh draft of the moor-burning bill, which had failed to reach the statute book in 1621, although this was rejected at its third reading, following attacks from Wentworth and William Noye.
In August 1624 Belasyse inherited an estate worth £4,000 a year. He may have felt that a small borough such as Thirsk did not reflect his new status, for at the general election of 1625 the seat passed to his eldest son, Henry. Belasyse kept a low political profile during the ascendancy of Sir John Savile*, but the latter doubtless supported his creation as Lord Fauconberg in May 1627 in order to win his support for the Forced Loan. Nevertheless, Belasyse was prepared to allow his son Henry to join with Wentworth to contest the shire election of 1628, in opposition to the Saviles. This alliance was quickly forgotten after Wentworth’s appointment as president of the Council in the North, perhaps because of the latter’s policy of maximizing the yield from recusancy compositions. Fauconberg and his eldest son publicly snubbed Wentworth at York, and thereby landed themselves in serious trouble with the Privy Council.
Tensions with Wentworth meant that Belasyse was a late convert to the royalist cause, but in the summer of 1642 he paid for the recruitment of the regiment commanded by his son John†. He fled to France after Marston Moor, returning shortly after the regicide in 1649, when he compounded for just over £5,000. Two-thirds of his estate was then sequestrated for recusancy until his death on 18 Apr. 1653. The chief beneficiary of his will, written shortly after his return from France, was his second son, now Lord Belasyse, but several servants were assigned £100 ‘to be disposed of by them accordingly as I have directed and declared my mind to them’, a phrase which may have concealed Catholic bequests.