Roman Christianity was late arriving in Ireland because the Roman armies never invaded the island. Consequently, Roman culture, and its brand of Roman Christianity, had little influence on early Irish Christianity. Because the educated class of the Celts, the Druids, had a long history of educational excellence and philosophic curiosity, they welcomed the new religion into Ireland as they did all new information. The ancient Greeks did student exchanges with the Druids, whom they considered the other great philosophers in Europe. Perhaps the most famous Greek scholar to study under the Druids was Pythagoras. 