The first Celtic monasteries were merely settlements where the priests and laity, men, women, and children — lived together as a clan.  Later, actual monasteries of monks and nuns were formed, and later the cloistered life was developed. The desire for extreme austerity, in contrast to licentious hedonism of continental Europe, has been a hallmark of Irish monasticism to today.  The eremitical life was regarded as the height of monasticism, and the means of perfection have been austerity, poverty, obedience, celibacy, fasting, prayer vigils, and hard work.

Irish monks are famous for preserving literature, history, and philosophy from ancient civilizations in Asia Minor and Europe by copying and translating ancient documents and literature in addition to copying contemporary manuscripts of various genres.  In the Dark Ages, the monastic scribes preserved Western history in their scriptoria by diligently copying by hand, with quill and ink, borrowed and acquired scrolls and books.

Irish monks and friars have also gained renown by leaving their cloisters to re-evangelize continental Europe and proselytize in Africa and the Americas.