- Source: Ioannes I
- Ioannes I dari Trebizond
- Ioannes I Tzimiskes
- Orhan
- Kekaisaran Romawi Timur
- Andronikos I dari Trebizond
- Ioannes Pitzigaudes
- Sebastokrator
- Nikephoros I Komnenos Doukas
- Alexius I dari Trebizond
- Ioannes Malalas
- Ioannes I
- John I Tzimiskes
- Ioannes (given name)
- Pope John Paul I
- Pope John I
- AIMA prophecy
- Ioannes II
- Ioannes Paulus
- John the Baptist
- Giovanni Giustiniani
Ioannes I (Greek: Ἰωάννης A΄, "John I") may refer to:
Patriarch John I of Constantinople (c. 347–407)
John I Tzimiskes (c. 925–976), Byzantine Emperor
John I Doukas of Thessaly (c. 1240–1289)
See also
John I (disambiguation)
Ioannes II (disambiguation)