- Petronibus, Ludovicus Salimbeni de1
- Petrus, de Herenthals, 1322-1390 or 13911
- Phaedra (Greek mythological character)1
- Phalaris, Tyrant of Agrigentum, active 6th century B.C.1
- Pharmacology1
- Philip III, King of Spain, 1578-16211
- Philip IV, King of Spain, 1605-16651
- Philosophers1
- Phlebotomy1
- Physical appearance of Jesus Christ1
- Physical sciences1
- Physics1
- Physics (Aristotle)1
- Piccinino, Nicolo, -14441
- Piccolomini d'Aragona, Antonio di Nanni Todeschini, Duke of Amalfi1
- Piccolomini di Castiglia e d'Aragona, Giacomo di Nanni Todeschini1
- Piccolomini, Agnes1
- Piccolomini, Andrea1
- Piccolomini, Andrea de1
- Piccolomini, Andreas1