Title
- Novellas1
- Oculus sacerdotis1
- Odes1
- Office of the Dead1
- Old Testament1
- Oleum effusum nomine tuum1
- On buying and selling1
- On the Anger of God1
- Opera1
- Orations1
- Order1
- Ordinal1
- Ordinatio totius officii divini1
- Ordo judicarius1
- Ordo unctionis infirmorum eorumque pastoralis curae1
- Panormia1
- Papal documents1
- Partial Chronicon pontificum et imperatorum with continuations and list of bishoprics1
- Paschale carmen1
- Passio sancti Blasii1