There’s many a detail I would quibble with in this book, but Cahill gets it spot on for his two big ideas: the vital role played by Irish monks in saving and renewing the culture of Europe after the fall of Rome, and the extraordinary personality of Patrick. First, the monks. While it’s true that preference of modern scholarship is to emphasise the continuity between the late Empire and the early Barbarian states, yet this was a continuity that was mainly political – the successor kings appropriated as much of the machinery of the Roman state, in particular its tax gathering abilities, as they could manage. But the cultural continuity was limited, and the barbarians, apparently self conscious about their own cultural limitations, brought little to the part.

The Irish, on the other hand, were never part of the Empire. Once they adopted Christianity, and it gave them written voice and language, they kept what was best of their own tradition, while teaching and transmitting, with all the vigour and enthusiasm of those who had never felt the Roman lash, all the best of Classical and, naturally, Christian thought. But moving on to Patrick, none of this would have happened without him. Although other missionaries may have been conflated with Patrick, it’s clear that he still had both the courage and, even more importantly, the open mindedness to be the first in the West to go beyond the bounds of Empire, to go beyond the ends of the world. Patrick went where his vision, his dream, told him to go. But others may have received such a commission, only to recoil before its unthinkableness. Patrick went. And he changed the world.