- Manuscripts, Spanish3
- Mary, Queen of Scots, 1542-15871
- Massachusetts2
- Massachusetts--Boston2
- Massachusetts--Williamstown1
- Mexico1
- Mexico--Mexico City1
- Monasteries1
- Monasterio de San Jerónimo de Monte Olivete (Sant Pere de Ribes, Spain)1
- Monasterio de San Jerónimo de la Murtra (Badalona, Spain)1
- Monasterio de San Jerónimo del Valle de Hebrón (Barcelona, Spain)1
- Morales family1
- Morales, Andrés de, active 1683-16851
- Morales, Francisco de, active 1683-16851
- Morales, Nicolás de, active 1683-16851
- Naper, Alexander1
- Nobility4
- Ochoa family1
- Oviedo family1
- Oviedo, Francisco de, 1728-1