In most accounts of Irish history, the focus is on the political rivalry between Unionism and Republicanism. But the roots of the Irish conflict are profoundly and inescapably religious. As Marcus Tanner shows in this vivid, warm, and perceptive book, only by understanding the consequences over five centuries of the failed attempt by the English to make Ireland into a Protestant state can the pervasive tribal hatreds of today be seen in context. Tanner traces the creation of a modern Irish national identity through the popular resistance to imposed Protestantism and the common defense of Catholicism by the Gaelic Irish and the Old English of the Pale, who settled in Ireland after its twelfth-century conquest.

The book is based on detailed research into the Irish past and a personal encounter with today's Ireland, from Belfast to Cork. Tanner has walked with the Apprentice Boys of Derry and explored the so-called Bandit Country of South Armagh. He has visited churches and religious organizations across the thirty-two counties of Ireland, spoken with priests, pastors, and their congregations, and crossed and re-crossed the lines that for centuries have isolated the faiths of Ireland and their history.