Celtic Christianity

"Enter the Celtic missionaries. Out to the west, in the islands of Britannia and Hibernia, constant pagan pressure, like the force exerted on carbon, had resulted in a hard, brilliant, diamondlike Christian spirituality. It was biblical, it was ascetic, it was scholarly, it was uncompromising and it was evangelistic. Impelled by peregrinatio, a kind of divine wanderlust, pioneer missionaries such as Columban, Fursey, Willibrod and Boniface roamed the European mainland, converting pagans and tearing down their shrines, preaching affective religion to Christians, challenging monks and priests to live up to their vocations and establishing centers for contemplation and study. These puritanical and purifying missionaries exercised a profound influence on Charlemagne."

Charlemagne - Derek Wilson, pg. 7