- Medicine1
- Medina Sidonia, Alonso Pérez de Guzmán, duque de, 1550-16191
- Medina Sidonia, Juan Alonso de Guzmán, Duque de, -15581
- Medina, Francisco de, 1544-16151
- Missions1
- Missions, Portuguese1
- Montserrat (Abbey)1
- Mosteiro de S. Mónica (Lisbon, Portugal)1
- Natural law1
- Netherlands1
- Nobility1
- North, Edward North, Baron, 1496?-15641
- Obstetrics1
- Order of the Golden Fleece1
- Orders of knighthood and chivalry1
- Pasture, Right of1
- Pelayo, King of Asturias, -7371
- Philip IV, King of Spain, 1605-16651
- Pictorial works1
- Poetry1