in 1765 assisted Dr. Charles Lucas (1713–1771) [q. v.] in passing a bill (Act 5, Geo. III) for the better regulation of trials in cases of treason, whereby a copy of the indictment was to be furnished to prisoners and counsel assigned them. For his services he received a pension of 200l., which he vacated on his appointment to the lucrative post of weighmaster of Cork. In 1774 he established a charitable institution in the city for the relief of persons confined for small debts. He died in the spring of 1776, bequeathing the bulk of his property to his eldest son, Henry (see below). Two other sons, Christopher and Richard, died in the king's service, the former as a soldier, of yellow fever, in the West Indies, the latter as lieutenant in the navy, while on board his majesty's ship Thunderer, lost on the West Indian station in the great hurricane of October 1779. A fifth son, Robert, was drowned in saving the life of John when as boys they were bathing together.
John, whose youth was passed at Glasheen, on the outskirts of Cork, inherited from his father a small fortune of 3,000l. Intended from the first for the legal profession, he received a liberal education at home and at Trinity College, Dublin, where he graduated B.A. in 1787. He was called to the Irish bar in the following year, and in 1792 he accompanied his brother Henry on a visit to his family in France. Here he became imbued with the political principles of the Revolution, though at first not so deeply as to prevent him, it is said, when paying a visit to Versailles, from falling on his knees and vowing to plunge a dagger in the heart of every Frenchman he met if a hair of the head of Marie-Antoinette were touched. He was, however, present at the execution of Louis XVI in January 1793, and, returning to England in the same packet-boat as Daniel O'Connell, he disgusted him by exhibiting a handkerchief which he exultingly declared to have been steeped in the murdered monarch's blood. Having established himself in Dublin, and being of frugal habits, buying hardly anything except books, he not merely managed to retain his fortune intact, but was making a fair income at the bar when he was drawn within the vortex of Irish politics.
It is doubtful when precisely he became a United Irishman; but in a speech in the House of Lords in July 1793, Lord Clare alluded to him and his brother as ‘members of the French Jacobin Club … in the pay of that society to foment sedition in this country.’ The statement was wide of the truth, but Sheares occupied the chair at a meeting on 16 Aug. when an address was voted to the Hon. Simon Butler and Oliver Bond [q. v.] on their release from prison, and was with difficulty restrained from carrying a message from the former to the lord chancellor. He showed his sympathy with the revolutionists by attending the funeral of the Rev. William Jackson [q. v.] in May 1795, and when the ‘Press,’ a violent anti-government newspaper, was started by Arthur O'Connor [q. v.] in October 1797, Sheares became a frequent contributor to it. Owing to the editor's acceptance of an article by Sheares signed ‘Dion,’ and addressed to Lord Clare, as ‘the Author of Coercion,’ the paper was suppressed on 6 March 1798, the day on which the article was to have appeared. The article was subsequently published in a volume called ‘The Beauties of the Press,’ London, 1800, pp. 566–74, and is reprinted by Madden in ‘United Irishmen,’ 1st ser. ii. 92–103. In the society itself Sheares possessed little influence, and apparently took only a languid interest in its affairs, being, it is said, mainly responsible for the unorganised state of county Cork, which had been assigned to him and his brother. His practice at the bar, owing to the hostility of Lord Clare, did not prosper, and about Christmas 1797 he spoke of going to America. But his conduct was governed by his affection for a young lady of the name of Steele, to whom he had become greatly attached in 1794, but whose marriage with him was opposed by her mother on the ground of the laxity of his morals.
After the arrests at Bond's house on 12 March 1798, when Sheares and his brother were elected to vacant places in the directory, his whole nature seemed to undergo a change. He was indefatigable in his exertions to repair the loss the society had suffered. The rising was fixed for 23 May. On the 10th of that month he made the acquaintance of John Warneford Armstrong, a captain in the King's County militia, who afterwards informed against him. Sheares revealed to him his plan for corrupting the army. Armstrong's professions of sympathy completely deceived Sheares. The brothers were arrested on 21 May, and confined in Kilmainham gaol. On 4 July they were arraigned on a charge of high treason before Chief-justice Carleton, but the trial was postponed till the 12th. On the eve of his trial Sheares wrote to his sister Julia that, while he had no doubt about his own fate, he believed that Henry would escape. They were defended by Curran, Plunket, and McNally, but there is little doubt that the prosecution were beforehand fully acquainted with the line of defence adopted by them (through
