Presbyterian Church in Ireland in the context of "Presbyterianism"

Unionism in Ireland is a political tradition that professes loyalty to the crown of the United Kingdom and to the union it represents with England, Scotland and Wales. The overwhelming sentiment of Ireland's Protestant minority, unionism mobilised in the decades following Catholic Emancipation in 1829 to oppose restoration of a separate Irish parliament. Since Partition in 1921, as Ulster unionism its goal has been to retain Northern Ireland as a devolved region within the United Kingdom and to resist the prospect of an all-Ireland republic. Within the framework of the 1998 Belfast Agreement, which concluded three decades of political violence, unionists have shared office with Irish nationalists in a reformed Northern Ireland Assembly. As of February 2024, they no longer do so as the larger faction: they serve in an executive with an Irish republican (Sinn Féin) First Minister.

Unionism became an overarching partisan affiliation in Ireland late in the nineteenth century. Typically Presbyterian agrarian-reform Liberals coalesced with traditionally Anglican, Orange Order allied, Conservatives against the Irish Home Rule Bills of 1886 and 1893. Joined by loyalist labour, on the eve of World War I this broad opposition to Irish self-government concentrated in Belfast and its hinterlands as Ulster unionism and prepared an armed resistance—the Ulster Volunteers.

Belfast (/ˈbɛlfæst/ , BEL-fast, /-fɑːst/, -⁠fahst; from Irish: Béal Feirste [bʲeːlˠ ˈfʲɛɾˠ(ə)ʃtʲə]) is the capital city and principal port of Northern Ireland, standing on the banks of the River Lagan and connected to the open sea through Belfast Lough and the North Channel. It is the second-largest city in Ireland (after Dublin), with an estimated population of 352,390 in 2024, and its metropolitan area has a population of 671,559.

Occupied since at least the Bronze Age, it was chartered as an English settlement in 1613. The town's early growth thereafter was driven by an influx of Scottish Presbyterians. Their descendants' disaffection with Ireland's Anglican establishment contributed to the rebellion of 1798, and to the union with Great Britain in 1800—later regarded as a key to the town's industrial transformation. When granted city status in 1888, Belfast was the world's largest centre of linen manufacture, and by the 1900s her shipyards were building up to a quarter of total United Kingdom tonnage.

The Society of United Irishmen was a sworn association, formed in the wake of the French Revolution, to secure representative government in Ireland. Despairing of constitutional reform, and in defiance both of British Crown forces and of Irish sectarian division, in 1798 the United Irishmen instigated a republican rebellion. Their suppression was a prelude to the abolition of the Irish Parliament in Dublin and to Ireland's incorporation in a United Kingdom with Great Britain.

Espousing principles they believed had been vindicated by American independence and by the French Declaration of the Rights of Man, the Presbyterian merchants who formed the first United society in Belfast in 1791 vowed to make common cause with their Catholic-majority fellow countrymen. Their "cordial union" would upend the landed Anglican Ascendancy and hold government accountable to a reformed Parliament.

Robert Stewart, 2nd Marquess of Londonderry (18 June 1769 – 12 August 1822), usually known as Lord Castlereagh, derived from the courtesy title Viscount Castlereagh (UK: /ˈkɑːsəlreɪ/ KAH-səl-ray) by which he was styled from 1796 to 1821, was an Irish-born British statesman and politician. As secretary to the Viceroy in Ireland, he worked to suppress the Rebellion of 1798 and to secure passage in 1800 of the Irish Act of Union. As the Foreign Secretary of the United Kingdom from 1812, he was central to the management of the coalition that defeated Napoleon, and was British plenipotentiary at the Congress of Vienna. In the post-war government of Lord Liverpool, Castlereagh was seen to support harsh measures against agitation for reform, and he ended his life an isolated and unpopular figure.

Early in his career in Ireland, and following a visit to revolutionary France, Castlereagh recoiled from the democratic politics of his Presbyterian constituents in Ulster. Crossing the floor of the Irish House of Commons in support of the government, he took a leading role in detaining members of the republican conspiracy, the United Irishmen, his former political associates among them. After the 1798 Rebellion, as Chief Secretary for Ireland he pushed the Act of Union through the Irish Parliament. However, unable to overcome the resistance of King George III to the Catholic Emancipation that they believed should have accompanied the creation of a United Kingdom, both he and Prime Minister William Pitt resigned.