 The Chronicle of Ireland records that in 431 AD Bishop Palladius arrived in Ireland on a mission from Pope Celestine I to minister to the Irish " already believing in Christ " . The same chronicle records that Saint Patrick , Ireland 's best known patron saint , arrived the following year . There is continued debate over the missions of Palladius and Patrick but the consensus is that they both took place and that the older druid tradition collapsed in the face of the new religion . Irish Christian scholars excelled in the study of Latin and Greek learning and Christian theology . In the monastic culture that followed the Christianisation of Ireland , Latin and Greek learning was preserved in Ireland during the Early Middle Ages in contrast to elsewhere in Europe , where the Dark Ages followed the decline of the Roman Empire . 
