Author
- Odo of Meung1
- Origen1
- Osbern of Gloucester1
- Papias1
- Piccolomini1
- Piccolomo Oltremonti1
- Pietro Parenzi1
- Podestà of Monticchiello (Italy)1
- Prosper of Aquitaine1
- Pseudo-Hippocrates1
- Ptolemy1
- Qadi Ayyad1
- Rabīʻah ibn Muḥammad Maʻmarī1
- Raginaldus Collus Rubeus1
- Richard Fishacre1
- Richard de Geveldale1
- Richard of Middleton1
- Robert de Gretham1
- Roger Bigod, 2nd Earl of Norfolk1
- Rogerius1