- Majolus, Saint, Abbot of Cluny, approximately 906-9941
- Manichaeism1
- Marina, Saint1
- Massachusetts--Williamstown1
- Materia medica, Vegetable1
- Mathematics1
- Missals (Service books)1
- Monasticism and religious orders1
- Monasticism and religious orders--Rules1
- Moral education1
- Musical notation1
- Mysteries and miracle-plays, English1
- Nautical charts1
- Neuland, Walter, active 14501
- Ninth century1
- Nobility1
- Norbert, of Xanten, Saint, approximately 1080-11341
- North, Edward North, Baron, 1496?-15641
- Oaths1
- Odilo, Saint, Abbot of Cluny, 962-1048 or 10491