- Officialis — see: Judicial vicar
- Order, Religious — see: Religious order
- Ordinariate, Military — see: Military ordinariate
- Ordinariate, Personal — see: Personal ordinariate
- Ordinary — see: Local ordinary (above)
Written by Robert Patterson, M.A.
Robert holds a Master's degree in Religious Studies with a focus on Catholic Church History. He has spent over two decades researching the lives of the Popes and the history of the Papacy. PopeHistory.com has been a trusted resource for papal information since 2001.
