Monks were the inhabitants of a monastery. They were isolated from the daily life of peasants and the upper classes, and because of the political dynamics of the Celtic peoples this put them in a position of superiority over priests.
- Education: Only the most intelligent peasant children along with noble and royal children were educated. They were taught Latin as well as mathematics and reasoning.
- Activities: Monkish habits varied by the particular Rules of the monastery they were in. Some monasteries believed that monks should do all the labor involved in maintaining the monastery. A small portion believed that monks should use no animal labor. But most monasteries carried on a tradition of copying manuscripts to add to their house, and reading the books as they copied them.
- Diet: St. David's rule insisted on a daily of almost exclusively bread and water. However, most "Rule"'s were much more generous, allowing for a balanced diet of meats, grains, and vegetables, much more balanced than the meat-focused meals of the warrior caste or the protein-lacking diets of the peasants.
- Intellectual: Besides copying manuscripts and the inevitable conversations that followed, monks traveled to other monasteries, occasionally partook of intellectual and spiritual meetings such as synods and councils.
- Medicine: Monasteries had the most advanced medicine of the period - they were relatively clean. A warrior/king/peasant who found his way to a monastery had a much better chance of surviving than usual. Monks were the usual caretakers of the diseased.