There has always been a tradition of armed resistance to the British military and political occupation of Ireland. This tradition generally only found effective expression when after a period of non-armed agitation, large sections of the Irish people, faced with the British government's denial of the legitimate demand for Irish independence, exercised the right to use armed struggle.

This was the case with the organisation from which modern Irish republicans trace their origins - the United Irishmen of the 1790s. Inspired by the example of the American War of Independence and by the democratic ideals of the French Revolution, the United Irishmen sought to unite the people of Ireland in a common effort to achieve equality and freedom. Choosing initially non-violent means to win their aims, the United Irishmen quickly met with a repressive response from the British government. It was only then that they exercised their right as Irish people to defend their liberty by the use of arms. It was a pattern that was to be repeated several times in the next century and a half.