- Ortiz family1
- Orto, Giovanni dall'1
- Ospedale degli Innocenti (Florence, Italy)1
- Otto I, Holy Roman Emperor, 912-9731
- Ovando, Nicolás de, approximately 1460-15111
- Oviedo family1
- Oviedo, Francisco de, 1728-1
- Oviedo, Gregorio de, 1721-17961
- Oviedo, Nicolás de, 1725-1
- Pablo de Santa Maria, Bishop of Burgos, approximately 1351-14351
- Pacheco de Silva, Juana1
- Pachisi1
- Paffiere, Arcangelo1
- Paffiere, Matteo1
- Paganelli, Roberto1
- Pagani, Angiola1
- Pagliaiolo, Cenni1
- Pago, Sapia di1
- Pain--Religious aspects--Christianity1
- Painted books1