For any not familiar with Thomas Cahill's Hinges of History series, "How the Irish Saved Civilization" is an incredible (and incredibly entertaining) read. Scholarly and faithful to the historical record, Cahill lays out how the Celtic saints and Scholars of the late classical period are responsible for preserving western culture as we know it.

Although the book is not specifically about Christianity, it is impossible to discuss Irish history without it; faith and life are so intertwined for the Irish that the two are impossible to separate. I was really able to see that while the beaurocracy of Rome grew ever more corrupt and entangled, the strain of Christianity preserved in Ireland was the closest thing that existed to Jesus' tolerant, charismatic religion, which bears little resemblance to international Catholicism today. While bishops and kings jockeyed for power in Italy, the saintly men and women of the church in Ireland carefully protected what remained of classical literature, philosophy and law, while practicing the simple, everyday style of Christianity that Jesus himself taught.

A great pity it remains that the Celtic church finally surrendered to Rome. Had it been the other way around, I think the Catholic Church wouldn't find itself as out of focus as it is now, dealing with scandal and declining attendance rather than spiritual growth.