Constantinus fuit cognomen, nomen imperiale, nomen papale. Hodie est praenomen masculinum.
- Constantinus I, Imperator Romanus (306-337)
- Flavius Tiberius Constantinus, Imperator Romanus Orientalis (578–582)
- Constantinus III, Imperator Romanus Orientalis (641)
- Constantinus IV, Imperator Romanus Orientalis (668–685)
- Constantinus V Copronymus, Imperator Romanus Orientalis (741–775)
- Constantinus VI, Imperator Romanus Orientalis (780–797)
- Constantinus VII Porphyrogenitus, Imperator Romanus Orientalis (913–959)
- Constantinus VIII, Imperator Romanus Orientalis (1025-1028)
- Constantinus IX Monomachus, Imperator Romanus Orientalis (1042-1055)
- Constantinus X Ducas, Imperator Romanus Orientalis (1059–1067)
- Constantinus XI Palaeologus, Imperator Romanus Orientalis (1448–1453)
- Constantinus, papa
- Constantinus Africanus, medicus, sexologus