 The Chronicle of Ireland records that in <unk> AD Bishop <unk> 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 <unk> and Patrick but the consensus is that they both took place and that the older <unk> 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 . 
