Time Line 303
Births
- 20,000 Martyrs of Nicomedia
- Martyrs of Caesarea
- Martyrs of Caesarea
- Martyrs of Nicomedia
- Martyrs of Nicomedia
- Martyrs of Nicomedia
- Martyrs of Nicomedia
- Martyrs of Novellara
- Martyrs of Nyon
- Martyrs of the Salarian Way
- Martyrs of Upper Egypt
- Saint Aaron of Caerleon
- Saint Abundius of Syria
- Saint Aceolus of Amiens
- Saint Adaucus of Phrygia
- Saint Agapes of Nicomedia
- Saint Agapius of Caesarea
- Saint Agathopus the Deacon
- Saint Alexander of Caesarea
- Saint Alexander of Nicomedia
- Saint Anastasius of Lérida
- Saint Anastasius of Nicomedia
- Saint Anthes of Salerno
- Saint Anthimos of Nicomedia
- Saint Anthimus of Rome
- Saint Apollo of Novellara
- Saint Aquilinus of Noyon
- Saint Arontius of Potenza
- Saint Audactus of Thibiuca
- Saint Barulas
- Saint Bono of Novellara
- Saint Calamanda of Calaf
- Saint Camerinus of Sardinia
- Saint Caprasius of Agen
- Saint Cassiano of Novellara
- Saint Castoro of Novellara
- Saint Christeta of Avila
- Saint Cisellus of Sardinia
- Saint Clement of Ancyra
- Saint Crescentinus
- Saint Cyriacus of Nicomedia
- Saint Cyriacus the Martyr
- Saint Damiano of Novellara
- Saint Diocletius of Osimo
- Saint Dionisio of Novellara
- Saint Dionysius of Caesarea
- Saint Domna of Nicomedia
- Saint Domna of Nicomedia
- Saint Domnina of Anazarbus
- Saint Doroteo of Nicomedia
Founded
Elevations
Other Events
- Diocletian begins a persecution of Christians
- Roman edict for the persecution of Christians issued by Emperor Valerius Maximianus Galerius
| 302 | 304 |