The First World War was a cause of the Easter Rising in 1916. First, John Redmond, leader of the Irish Parliamentary or Home Rule party, declared Irish support for the British war effort, and committed troops to the front line. He thought that if Irish Nationalists supported Britain at this time, as the Ulster Unionists had, they would later be rewarded with Home Rule. Many Irish Catholics joined the British Army to defend Belgium, a small Catholic country facing foreign invasion which they saw as much like Ireland. However, committing moderate Irish troops to abroad meant that the more hardline republicans were left at home. Furthermore, the Irish troops were not well treated in the army and were not granted their own brigade as the Ulster Unionist troops had been. The British Government's decisions to bring in conscription in Ireland when the number of troops willingly signing up dropped was faced with much anger. It was also felt by the Irish that the Ulster Division was kept away from danger while the Irish troops were not. Finally, many of the Irish Republican Brotherhood, the authors of the Rising, saw England's difficulty as Ireland's opportunity. The World War created the perfect moment for the Irish to strike for independence as the English were distracted abroad.
Moreover, emmigration is an important part of Irish history. It had the effect of removing the most disaffected members of society. However, with WWI emmigration had been curtailed and thus these dissatified elements of society remained in Ireland, leading to an atmosphere of rebellion.
However, this was not the sole cause of the Rising. The Rising was also influenced by the Gaelic Revival which saw an increase in the number of people learning the Irish language, playing Gaelic Games, and indeed poets and playwrights started putting Irish nationalist material on the stage at the Abbey Theatre. The Easter Rising has frequently been called 'the poets revolution' as a majority of the rebels were poets and intellectuals and were greatly influenced by the Gaelic Revival. The strength of the IRB's leadership was a cause of the Rising. Padraig Pearse was extremely patriotic and glorified rebellion and bloodshed. He believed in blood sacrifice, that Ireland would only become stronger if the blood of its people were shed. His strong religious beliefs were influential in ensuring that the Rising took place at Easter; he saw the rebels as Christ like, sacrifing themselves for Ireland's freedom. The rebels were aware that the Rising was unlikely to succeed militarily and yet they believed that eventually it would turn the tide of opinion in Ireland and lead to Irish freedom, which in the end it did. James Connolly, leader of the Irish Citizen Army, labelled Padraig Pearse a 'blithering idiot' as Connolly lamented the World War and working class men fighting against each other. He was a respected socialist who believed that Irish freedom was the first step to creating a socialist Ireland. Ireland could not achieve the socialist ideals of equality while it remained in the grasp of England. He hung the banner 'not for King nor Kaiser but for Ireland' from the Irish Citizen Army's Headquarters. He was key in the inclusion of many of the socialist aspects of the Irish Proclamation which was read by Pearse on the steps of the GPO on the morning of the 24th April. Thomas Clarke was the leading signatory of the Proclamation, being the oldest of the rebel leaders and greatly respected for his previous acts in furtherance of the republican cause.
Overall, the World War was important in the lead up to the Rising but rather than being seen as the main cause it is better understood as creating the country and the atmosphere in which a successful rebellion seemed conceivable. The convictions of the leaders, coupled with the Gaelic Revival, were fundamental in the Rising itself.