The French Revolution broke out in 1789 and convinced many Irish Presbyterians and members of the Church of Ireland that Catholics were not inherently conservative and incapable of progressive political change as had previously been assumed. The American Revolutionary Thomas Paine and his Rights of Man were extremely influential in promoting this ideal in Ireland. In September, 1791, Irishman Theobald Wolfe Tone published "Argument on Behalf of the Catholics of Ireland" which maintained that religious division was a tool of the elite to "…(balance) the one party by the other, plunder and laugh at the defeat of both" and put forward the case for unity between Catholic, Protestant and Dissenter. Tone's pamphlet was hugely influential. Tone and friend Thomas Russell became passionate fighters for Catholic Rights. A group of nine Belfast Presbyterians interested in reforming Irish Parliament read Tone's pamphlet and liked his ideas. They invited Tone and Russell to Belfast where the group met on October 14, 1791. At this first meeting, the group, which became known as the United Irishmen, passed the following three resolutions:
Except for Theobald Wolfe Tone and Thomas Russell, attendees at the first meeting were Presbyterian; most were involved in the linen trade in Belfast. The men involved were: William Sinclair, Henry Joy McCracken, Samuel Neilson, Henry Haslett, Gilbert McIlveen, William Simms, Robert Simms, Thomas McCabe and Thomas Pearce.
The movement became supporters of the Catholic Committee, who had been working to get Catholic Emancipation bills through Parliament, repeal the remaining Penal Laws and abolish the Tithe laws. This was to remove legal disabilities and was not an endorsement of Catholicism itself, as the United Irishmen's revolutionary allies in France were dechristianizing their new state. Their ultimate goal was to separate religion from politics.
Up to 1792 the Society was in line with Henry Grattan's views, but came to differ with him as to the best method of reform. Grattan followed Edmund Burke and felt that a gradual continuation of reform was the best course. This reform was opposed by the Protestant Ascendancy majority (elected by a few thousand men), and usually by the viceroy who was appointed by the government in London. The Society planned for a democratic system with 300 constituencies where all adult males were enfranchised, and inevitably a break with London.
Dublin soon followed Belfast's example by founding its own branch of the United Irishmen on 9 November. The organisation also linked up with the Catholic agrarian secret society the Defenders, and many of its cells operated as de facto United Irish branches. The movement quickly developed a strategy of spreading its ideals by means of pamphlets, leaflets, newspapers, ballads, "catechisms," and travelling emissaries. The Northern Star of Belfast was especially successful, both commercially and politically and had a wide readership until its suppression in 1797. The spread of the society was watched with growing alarm by the authorities and it was banned in 1793 following the declaration of war on France.
Worried by its presence, the Dublin administration conceded some reforms, allowing Catholics the vote, to become barristers and to enrol at Trinity College Dublin in 1793. The Hearth Tax paid by all households was abolished in 1795 and St Patrick's seminary at Maynooth was funded. However Catholics were also expected to join the militia and to inform on any United Irish activities.
In 1794, William Drennan became the first leader to be arrested and tried for sedition as the authorities began to react to the growth of the United Irishmen. In 1795, the Orange Order was founded as an auxiliary military force to counteract the spread of the United Irishmen on the ground and the loyalty of the hierarchy of the Catholic church was confirmed with the founding of Maynooth College the same year. At that stage the Church and the French republic were enemies. A French fleet carrying 15,000 troops set sail for Ireland in 1796, under General Hoche and spent days in sight of the Cork coast at Bantry Bay, but weather conditions meant it could not land. The British government responded to this near escape by sweeping up much of the United Irish leadership and imposed martial law from 2 March 1797, in an attempt to break the movement by the widespread use of terror during searches for weapons.23 May. However, information from informers led to the arrest of Lord Edward Fitzgerald on 18 May and foiled the plan to take Dublin that was the central core of the planned rebellion.
Although most of the United Irish leadership could not directly participate in the fighting, tens of thousands of followers took to the field and the resulting rebellion was severely hampered by the lack of leadership. The campaign met with little success except in Wexford and the weeks of extreme violence saw the rebellion degenerating at times into tit-for-tat sectarian massacres. The eventual arrival of 1,000 French troops in Killala, County Mayo in August was too little and too late to turn the tide for the United Irishmen (see part 2 of The Year of the French). In October, Wolfe Tone himself was captured when a supporting French fleet of 3,000 troops was intercepted and defeated by the Royal Navy near Lough Swilly.
Upon his capture Wolfe Tone famously said, "From my earliest youth I have regarded the connection between Ireland and Great Britain as the curse of the Irish nation, and felt convinced, that while it lasted, this country would never be free or happy. In consequence, I determined to apply all the powers which my individual efforts could move, in order to separate the two countries." After being denied a soldier's death by firing squad, Wolfe Tone cheated the hangman by cutting his throat.
The suppression of the rising was followed by a period of renewed repression but the United Irishmen still managed to survive as a functioning clandestine organisation. The decision to abolish the Irish Parliament resulting in the Act of Union 1800 that created the United Kingdom of Great Britain and Ireland played on sectarian hopes and fears and was to gradually erode the United Irishmen by playing Catholic against Protestant. This was despite the original recognition that the "bigotry" (to quote Prime Minister William Pitt) of the Protestant Parliament in Dublin had only contributed to sedition in Ireland.
Although the United Irishmen was a staunchly non-sectarian body which sought to unite all Irishmen, regardless of religion or descent many among their ranks were former Defenders, a term applied to many loosely connected, exclusively Catholic, agrarian resistance groups. Many of these men, as well as their Presbyterian counterparts in Ulster, had been shaped by the sectarianism that was prevalent in eighteenth century Ireland, and it was no mean feat to persuade Catholic, Protestant and Dissenter to put aside their differences and view each other simply as fellow Irishmen. Although the project met with remarkable success it was quickly recognised by the establishment that sectarianism was a useful ally in the fight against the United Irishmen. The formation of the Orange Order in 1795 was to prove particularly useful as it provided the Government with allies who had detailed local knowledge of the activities of their enemies. The brutal disarming of Ulster in 1797, where the United Irish had successfully radicalised both Protestant and Catholic saw thousands of Catholics driven from counties Antrim, Down and Armagh the murder, torture and imprisonment of hundreds of Protestants suspected of United Irish sympathies.
Religious division and hatred was therefore never completely buried and a minority of the Defenders did not reject completely their previous anti-Protestant outlook. During the course of the 1798 rebellion United Irish rebels pepretrated several sectarian massacres, most notoriously in County Wexford at Scullabogue and Wexford Bridge. While sectarianism undoubtedly played a part in many murders during the rising, religion was often taken as a signifier of loyalty or disloyalty by both sides, and the fact that often Protestants were amongst the perpetrators and Catholics among the victims of rebel massacres indicate that victims lost their lives for being perceived as loyalist as opposed to purely religious reasons. Such subtleties were ignored in the aftermath as the memory of such massacres was simplified and exploited in following years by loyalist politicians to cement the sectarian divide and to ensure the loyalty of Protestants to the English Crown. The fact that the vast majority of the estimated 15,000–30,000 people of both religions who lost their lives during the rebellion were victims of British and Loyalist troops was blithely ignored.
Most of the United Irish leadership and ideologues were born into Church of Ireland families; they became deists after 1790. This small part of the population - about 15% - included Wolfe Tone, Lord Edward Fitzgerald, Napper Tandy and Robert Emmet. While the United Irish had declared themselves to be non-sectarian from 1791, there were other liberal Protestants in the Irish Parliament who were also anti-sectarian and sought a more democratic franchise, such as Henry Grattan and John Curran.
The failure of Robert Emmet's rebellion in 1803 triggered the effective collapse of the Society of United Irishmen and the first half of the 19th century saw sectarianism replace separatism as the touchstone for political unrest in Ireland. Not until the Young Ireland movement in the 1840s was an attempt made to resurrect the non-sectarian ideals of the United Irishmen. However, the alliance between Catholic and Protestant was never fully regained as Protestants were drawn closer to a "British" identity through fear of having a perceived position of privilege eroded by the slowly growing political power of the Catholic majority. As a consequence, subsequent organised republican resistance to British rule in Ireland was largely confined to the Catholic population and seen as a threat by the majority of the Protestant population.