Wylde, Thomas (1780?–1813), cotton manufacturer and United Irishman, was born in England, one of the three sons and four daughters of Henry Wylde, owner of a cotton factory in the industrial village of Prosperous, Co. Kildare. Henry had settled in Ireland in the 1780s to avoid arrest after shipping arms to America during the American revolution, under a passport issued by Louis XVI. In 1792 Prosperous was wound down as an official concern, after a decade of tensions between the workers and proprietors. This may explain why the town became a centre of radical activity in the 1790s and why Thomas Wylde was drawn into the United Irishmen in 1798. On 22 May 1798 Capt. Richard Swayne of the Cork city militia took possession of Henry Wylde's cotton factory, situated opposite the barracks in Prosperous. On 24 May 1798 Thomas Wylde was one of the five United Irish commanders who led an attack on the barracks. Swayne was killed, and the remaining soldiers were trapped in the building and burned; seventy soldiers died. Wylde was arrested in Prosperous in October 1798 and charged with high treason. He was not tried until 1800 at Naas, when he was acquitted under the terms of the amnesty act, although he was kept in prison (probably in Naas gaol) for a further six months before his release in late 1800 or early 1801.
Once liberated, he moved to Dublin, where he was later joined by his father and family, who established a linen factory in Cork St. Wylde worked there until 1803, when he again engaged in revolutionary activity and accompanied Robert Emmet (qv) on a fact-finding mission to Kildare (8 March 1803). Wylde and his brother-in-law, John Mahon, then conducted similar missions to Co. Dublin and Co. Wexford. Their sorties lasted no more than a few days and only a handful of key rebels were visited, but their sanguine reports gave the impression that there was enough popular support to sustain a rebellion.
On 22 July 1803 Wylde, along with Mahon, was dispatched to Kildare to exhort local people to rise. According to Michael Quigley (qv), who was also Wylde's brother-in-law, Wylde and Mahon exaggerated the extent of the organisation in Dublin in order to enrol as many men as possible. When some of the Kildare leaders arrived in Dublin on the morning of 23 July and realised the truth, they accused Emmet of deception. Many of the Kildare men who travelled to Dublin got orders to return home en route; a few men who had actually arrived were sent back. Wylde was one of the leaders to emerge from the Thomas St. depot in Dublin but, quickly recognising revolt was futile, he retreated to Emmet's headquarters at Butterfield Lane, Rathfarnham. After the rebellion, with £300 offered for their capture, Wylde and Mahon concealed themselves first at Mahon's father's house at Greenhills near Rathcoffey, then at an alehouse at Cockbridge, and finally as carpenters at an old ruined building that had been converted into a windmill near Philipstown, King's Co. (Daingean, Co. Offaly), where Wylde's brother-in-law, Morrow, was the local jailer. They were informed on, but when the authorities attempted to arrest them on 10 December 1803 they escaped, shooting dead Capt. Charles Dodgson of the 4th dragoon guards and injuring Col. John Longfield. As a result an increased reward of £900 was offered for their arrests. They fled to Naas and then to Dublin, where they were concealed at the home of Lady Moira (qv) before sailing to America along with a fellow United Irishman, John Burke. Realising that their ship would be searched before departure, they evaded capture by persuading three friends to take their place on board, and then exchanged places after the search. It appears that Wylde spent the next ten years in New York; his death was reported in New York in Cox's Irish Magazine in June 1813.