With 450, mostly civilians, killed and 2,614 wounded, Britain exacted severe punishments upon the perpetrators of the rebellion. Seven men who had signed the Easter Proclamation, outlining the objectives of the rebels, were executed. The rebels quickly became martyrs in the eyes of the Irish and radicalized many who had previously been moderates.
The Irish Political Party, once dominant in English parliamentary politics, had advocated moderation and limited autonomy, but it became increasingly marginalized following the rebellion. Alternatives to the Irish Political Party emerged, and several organizations, including Sinn Féin and the Irish Republican Brotherhood, advanced nationalist goals.
To many, British domination was cultural and social as well as political. They felt that British goods, the British educational system, and the Anglican religion had erased Irish identity. Organizations such as the Gaelic League and the Gaelic Athletic Association provided outlets for the expression of Irish cultural heritage based on education, language, and literature.
Sinn Féin's success in the 1918 election secured its dominance in the independence movement. The Easter Uprising had occurred when Britain had been preoccupied with World War I, and Britain feared that a successful Irish separatist movement would spark similar revolts in its far-flung colonial holdings.
In 1918 Britain indicated that it would extend conscription to Ireland. The so-called conscription crisis further spurred and unified Irish nationalists. Rebels were encouraged by Woodrow Wilson's principles of self-determination, which intimated that every nation had the right to independence and sovereignty. In 1919 Irish representatives even traveled to attend the Paris Peace Conference in the hopes that Irish independence would be addressed during the postwar peace negotiations.
From 1919 to 1921 the progressive use of physical force effectively transformed the struggle into a guerrilla war. Much of the fighting began during the last 12 months of the conflict, which caused over a thousand deaths. British reaction was harsh; there were frequent police raids of nationalist houses and large scale arrests.
But British retaliation only escalated the violence. The Black and Tans, former servicemen who supported the British police, became notorious for violent tactics. Irish prisoners often went on hunger strikes as a form of political protest.
On November 21, 1920, known as Bloody Sunday, 26 people were killed when nationalists attacked British intelligence agents and the British police retaliated during a Gaelic football game. Martial law was imposed on parts of the country, and an attempt was made to negotiate peace.
On July 9, 1921, the two sides agreed to a truce. Éamon de Valera, then president of Sinn Féin and later president of the Dáil Éireann (the Irish parliament based in Dublin), met with British prime minister David Lloyd George several times over the summer of 1921. In these negotiations Valera insisted on a completely independent and unified state.
The British delayed granting independence but did agree to an Anglo-Irish Conference. In the fall of 1921 a three-person delegation from the Dáil was chosen to represent Ireland. The resulting Anglo-Irish Treaty, signed on December 6, 1921, created a new but divided Ireland consisting of a six-county Northern Ireland linked to Britain, but with its own form of home rule.
Mainly Protestant, the northern Ulster province had long opposed Irish independence. The remaining 26 counties formed a distinct Ireland with limited autonomy and ensured continued allegiance to the British monarch. With none of the major objectives met, the Irish delegation returned to angry resistance from the rest of the Dáil cabinet.
Valera, who had decided not to participate in the conference, had instructed the delegation to consult with the rest of the cabinet prior to agreement on central issues and to send a draft of the treaty for review before signing it, but the delegation had not done so.
Michael Collins, representing the delegation, continued to support the treaty, while Valera remained adamantly opposed and continued to press for complete Irish independence. A bitter civil war between those opposing and those supporting the treaty ensured that the violence continued.