Title
- Ordinary of arms1
- Ordinary of the Mass4
- Ordinatio totius officii divini1
- Ordo benedicendi oleum catechumenorum et infirmorum et conficiendi chrisma1
- Ordo dedicationis ecclesiae et altaris1
- Ordo exsequiarum1
- Ordo judicarius2
- Ordo judiciorum1
- Ordo missae2
- Ordo unctionis infirmorum eorumque pastoralis curae1
- Oreste e Pylade1
- Organon2
- Original leaves from famous Bibles, nine centuries 1121-1935 A.D. ...1
- Orthographia1
- Orthographical text13
- Otia imperialia1
- Ottoman Turkish expansion on qaṣīdat al-Burdah1
- Ottoman Turkish music6
- Ottoman letters1
- Ottoman texts3