Constantine (son of Basil I)

Constantine
Emperor of the Romans
Constantine (right) with Emperor Basil (left)
Byzantine co-emperor (with Basil I)
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.