- Manuscripts, English1
- Manuscripts, English (Middle)1
- Manuscripts, French1
- Manuscripts, German1
- Manuscripts, Medieval1
- Manuscripts, Portuguese1
- Manuscripts, Turkish1
- Maria Anna Josefa, Queen, consort of John V, King of Portugal, 1683-17541
- Marriage (Canon law)1
- Marriage (Canon law)--Dispensations1
- Marshals1
- Massachusetts--Boston1
- Maximilian I, Holy Roman Emperor, 1459-15191
- Mayenne, Charles de Lorraine, Duc de, 1554-16111
- Medicine1
- Medicine--Formulae, receipts, prescriptions1
- Medina, Francisco de, 1544-16151
- Mehmed II, Sultan of the Turks, 1432-14811
- Missions1
- Montserrat (Abbey)1