Title
- On Catholic faith1
- On being and essence1
- On buying and selling1
- On diphthongs1
- On generation and corruption2
- On the eternity of the world1
- On virtue1
- Opera5
- Operationes Ihesu Christi1
- Ophthalmology text1
- Opuscula2
- Oratio ad immortalitatem illustriassimae nec non famigerratissimae laudis1
- Oratio in laudem rei publicae venetorum1
- Orationes3
- Orations4
- Orator ad Brutum1
- Order2
- Order for peaceable behavior1
- Order of the Egyptian Fathers1
- Ordinal5