This book examines the political transformation and radicalisation of Ireland between the outbreak of the First World War, August 1914 and Sinn Fein's landslide electoral victory in December, 1918. It argues, through a novel application of theories of ethno-symbolism and social movement theory, that the myths, memories and symbols of the Irish nation formed the basis for interpretation of the events of the Easter Rising, and that this interpretation stimulated members of the Irish nation to support radical nationalism. The book calls this phenomenon the Cultural Trigger Point. Through an examination of a variety of sources, the book traces, in particular, the impact of the Great War on cultural and religious nationalism, and its role in the rise of radical Irish nationalism.