How the Irish Saved Civilization: The Untold Story of Ireland's Heroic Role from the Fall of Rome to the Rise of Medieval Europe

The last three decades of Patrick’s life were an era of significant transformation in the West as the Roman Empire definitively ended. Cahill notes that the historical writing on Europe in that era focuses on Rome’s fall while neglecting the changes happening on Europe’s fringes, such as in Ireland. In his view, as former Roman provinces plunged into disorder, Ireland’s warrior society became more "civilized" through Patrick’s Christian mission.

Patrick succeeded in converting the Irish because he Christianized their spiritual values while removing their fear of death and of their ferocious gods. He preached that the Irish could be courageous, a quality that Cahill reiterates as one of their signature virtues, while also living in peace. Patrick, like the Irish pagans, viewed the world as a mystical place, but one that is under the power of a compassionate deity rather than subjected to the whims of the malicious and fickle gods who sought to entrap the heroes of Irish legends.

Christianity offered a spiritual view under which suffering was not permanent. Cahill claims that medieval Christianity was born in Ireland. The apostle to the Irish created a world for the Irish that the Romans could not, because he "could speak believably of the superabundance of a God who in response to humble prayer feeds his lost and wandering people with heavenly manna—and a crew of lost and starving sailors with a herd of very earthly pigs" (131).

Patrick drew on ideas that were already familiar to the Irish, notably the notion of the world as enchanted. One of his greatest challenges, however, was dealing with the pre-Christian ritual of human sacrifice, which the Irish believed was necessary to appease their fickle deities. Patrick suggested instead that the God of Christianity wanted humans to live for him and make sacrifices that did not involve death. The archeological finds known as Gundestrup Cauldron and Ardagh Chalice serve as evidence of shifting beliefs from the Celtic to the Christian cultures. The cauldron, which was tossed into a Danish swamp as an offering, depicts the Celtic gods receiving human and animal sacrifices. Yet it also depicts Cernunnos, a god of fertility and life, a “prehistoric Saint Francis, ruling his peaceable kingdom” (142). The latter is a Christian communion cup that commemorates Christ’s sacrifice: “[…] the Chalice has become the druidic Christian smith’s thanksgiving, his deo gratis” (144).