This first volume in A Treatise on Northern Ireland illuminates how British colonialism shaped the formation and political cultures of what became Northern Ireland and the Irish Free State. Contrasting colonial and sectarianized accounts of modern Irish history, Brendan O''Leary shows that a judicious meld of these perspectives provides a properly political account of direct and indirect rule, and of administrative and settler colonialism. The British state incorporated Ulster and Ireland into a deeply unequal Union after four re-conquests over two centuries had successively defeated the Ulster Gaels, the Catholic Confederates, the Jacobites, and the United Irishmen¿and their respective European allies. Founded as a union of Protestants in Great Britain and Ireland, rather than of the British and the Irish nations, the colonial and sectarian Union was infamously punctured in the catastrophe of the Great Famine. The subsequent mobilization of Irish nationalists and Ulster unionists, and