- Margaret, of Antioch, Saint1
- Marina, Saint1
- Marriage--Moral and ethical aspects1
- Marriage--Religious aspects1
- Marriage--Religious aspects--Christianity1
- Mary, Blessed Virgin, Saint, in the liturgy1
- Masorah1
- Mass--Celebration1
- Mathematics, Arab1
- Mathematics, Greek1
- Mathematics, Medieval1
- Matthias I, King of Hungary, 1443-14901
- Maurice, Saint, -approximately 2871
- Maximus, of Turin, Saint, active 4th century-5th century1
- Mechanics1
- Medicine, Greek and Roman1
- Medicine, Magic, mystic, and spagiric1
- Medicine, Persian1
- Mediterranean Region1
- Mediterranean Sea1