Ulster. The Great War was the single most crucial factor influencing the course of Irish history from the second decade of the 20th century, creating circumstances which led to total and irreversible political polarisation and to partition in Ireland. Initially it split the Irish Volunteers, who were raised to safeguard the granting of Home Rule and resist the secession of Ulster by the Ulster Volunteers from what they claimed was a coercive All-Ireland Home Rule settlement, into two opposing camps. These were, the larger National Volunteers – supporting the Allied war effort and subsequently in combat on the Western Front and in Gallipoli. And secondly the minority group of Volunteers who remained in Ireland and staged the Easter Rebellion in April 1916, proclaiming an Irish Republic, virtually unimaginable without the backdrop of the European conflict. Belated reappraisal Alarmed by the changed and volatile situation in Ireland the Prime Minister H. H. Asquith, following prolonged discussions, announced on 25 May 1916 to the House of Commons that he had agreed to undertake negotiations to bring about a permanent Home Rule settlement in Ireland. Lloyd George, then Minister for Munitions, was then sent to Dublin to offer this to the leaders of the Irish Parliamentary Party, John Redmond and John Dillon. The scheme revolved around partition, officially a temporary arrangement, as understood by Redmond. Lloyd George however gave the Ulster leader Carson a written guarantee that Ulster would not be forced in. A supreme master of political blandishment, he was able to keep the rival parties in play week after week in the hope that a settlement was at last possible. His tactic was to see that neither side would find out before a compromise was implemented. The country north and south, as well as the Cabinet, were divided on the issue. Joseph Devlin, the Ulster Nationalist leader, had won support in Belfast on 4 July for temporary exclusion of six counties. A modified Act of 1914 as "Headings of a settlement as to the Government of Ireland" had been drawn up by the Cabinet on 17 June. The formula then had two amendments enforced on 19 July by Unionists – permanent exclusion and a reduction of Ireland's representation in the Commons. This was informed by Lloyd George on 22 July 1916 to Redmond, who accused the government of treachery. The government bowed to the combined opposition of Unionists who never had