Former Owner
- Oric Bates2
- Orlandus de Fatiis1
- Oswald Carl Friedrich von Seilern und Aspang2
- Otto Ege52
- Otto Haas1
- Otto Jahn1
- Otto Orren Fisher2
- Otto Vollbehr2
- Otto Walter Fuhrmann1
- Owen D. Young1
- P. Desq2
- P. J. De Mat1
- Pandit Gobindpurshad1
- Pangracius Chrewczer1
- Paolo Gallo1
- Paolo Giovio4
- Paolo Vimercati Sozzi2
- Parish Church of Waldhausen im Strudengau1
- Park Abbey1
- Parroco di Taviano, Luigi Bruno, active 20th century1