- Manuscripts, Renaissance150
- Manuscripts, Spanish17
- Manuscripts, Tzutuhil1
- Marginalia3
- Maria Anna Josefa, Queen, consort of John V, King of Portugal, 1683-17541
- Maronite rite (Catholic Church)4
- Maronite rite (Catholic Church)--Liturgy5
- Marriage (Canon law)1
- Marriage (Canon law)--Dispensations1
- Marriage--Moral and ethical aspects1
- Martyrdom1
- Martyrs1
- Mary Magdalene, Saint4
- Mary, Blessed Virgin, Saint35
- Mass11
- Mass (Music)1
- Mass--Celebration1
- Massachusetts--Boston10
- Massachusetts--Northampton5
- Massachusetts--Wellesley12