Author
- Onasander1
- Order of Saint Michael1
- Order of the Argonauts of Saint Nicholas1
- Order of the Garter1
- Orderic Vitalis1
- Osbern of Gloucester1
- Palazzo degli Anziani1
- Panormitanus1
- Paolo da Firenze1
- Paschal II1
- Paschasius Radbertus1
- Paschualis Bernardus1
- Patrick Graham, 1st Lord Graham1
- Paul of Venice1
- Paul the Deacon1
- Paulus Melissus1
- Pedro de Serra1
- Pere Marsili1
- Pere Rossell1
- Perets ben Yitsḥak Ghirondi1