| Constantine | |
|---|---|
| Emperor of the Romans | |
&sq=&lang=&file=File:INC-3051-r_%D0%A1%D0%BE%D0%BB%D0%B8%D0%B4._%D0%92%D0%B0%D1%81%D0%B8%D0%BB%D0%B8%D0%B9_I._%D0%9E%D0%BA._867%E2%80%94886_%D0%B3%D0%B3._(%D1%80%D0%B5%D0%B2%D0%B5%D1%80%D1%81).png) Constantine (right) with Emperor Basil (left) | |
| Byzantine co-emperor | |
| Reign | c. January 868 – 3 September 879 |
| Predecessor | Basil I (alone) |
| Successor | Basil I and Leo VI |
| Born | Between 855 and c. 865 |
| Died | 3 September 879 |
| Betrothed | Ermengard of Italy |
| Dynasty | Macedonian dynasty |
| Father | Basil I, possibly Michael III |
| Mother | Maria, possibly Eudokia Ingerina |
Constantine (Greek: Κωνσταντῖνος, translit. Kōnstantīnos; born between 855 and c. 865, died 3 September 879) was a junior Byzantine emperor, alongside Basil I as the senior emperor, from January 868 to 3 September 879. His parentage is a matter of debate, but historians generally assume him to be the son of Emperor Basil I (r. 867–886) and his first wife Maria or second wife Eudokia Ingerina; other theories include him being the son of Emperor Michael III (r. 842–867) and Eudokia. Constantine was made co-emperor by Basil in c. January 868. He was engaged to Ermengard of Italy, the daughter of Holy Roman Emperor Louis II, in 870/871, but it is not known if he married her; some sources suggest he did, and others argue that there is no concrete evidence.
Constantine was the intended heir of Basil and as such received much attention from him and accompanied him on military campaigns, including one in Syria, for which he shared a triumph. In comparison, his younger brother, Leo VI (r. 886–912), was made co-emperor merely to secure the imperial lineage and bolster legitimacy. However, Constantine died of fever on 3 September 879, before his father. After his death, Leo became the primary heir, and another brother, Alexander (r. 912–913), was raised to co-emperor.