evidence: The conflict in Northern Ireland — the Troubles — in its violent form spanned three decades, from about 1968 to 1998. It led to the loss of thousands of lives and even more casualties, affecting Catholics and Protestants; paramilitaries and civilians in the North; British security forces serving in Northern Ireland, England, and on the European continent; and British civilians who were victims of IRA attacks in England. The violence caused billions of dollars of economic harm and left deep social and psychological scars. It had its roots in the complex history of Ireland’s relationship with Great Britain, especially the settlement that led to the Anglo-Irish Treaty of 1921 and the partition of the island into the Irish Free State and the "province" of Northern Ireland, the six northern counties on the island that opted out of the Irish Free State under the provisions of the treaty. The source of the Northern Ireland conflict was, in part, political — the legacy of the dispute among Irish nationalists about whether to accept, even temporarily, the partition of Ireland. It was also social and economic. While Catholics made up most of the island, Protestants composed the majority in the six Ulster provinces.