Author
- Notre-Dame de Chartres1
- Onasander1
- Order of the Argonauts of Saint Nicholas1
- Origen1
- Osbern of Gloucester1
- Otto III1
- Paschal II1
- Paschasius Radbertus1
- Paschualis Bernardus1
- Paul of Aegina1
- Pedro de Serra1
- Pere Marsili1
- Peter Cantor1
- Peter Paludanus1
- Peter Pascual1
- Peter, Constable of Portugal1
- Petrus Alphonsi1
- Petrus Aureolus1
- Petrus de Braco1
- Petrus de Isolella1