Constantine, son of Theophilos

Amorian or Phrygian dynasty
Chronology
Michael II		820–829
with Theophilos as co-emperor, 822–829
Theophilos		829–842
with Constantine (c. 833–835) and Michael III (840–842) as co-emperors
Michael III		842–867
under Theodora and Theoktistos as regents, 842–855, and with Basil I the Macedonian as co-emperor 866–867
Succession
Preceded by Leo V and the Nikephorian dynasty		Followed by Macedonian dynasty

Constantine (Greek: Κωνσταντῖνος, between 821/22 and 829 – c.830 or at the latest 835) was a prince of the Byzantine Empire and co-emperor.

He was probably the eldest son of emperor Theophilos and Theodora. He had four sisters (Thekla, Anna, Anastasia, Pulcheria, Maria). As Theophilos succeeded his own father Michael II as basileus on 2 October 829, Constantine became heir to the throne. Soon afterwards he was crowned co-emperor and he appears as such on the coins of his father. He died in childhood and was buried in the Church of the Holy Apostles at Constantinople.

There is little clarity as to the dates of his birth, coronation and death, but according to the Prosopographie der mittelbyzantinischen Zeit he was born in the (late) 820s and died before 831. In any case, only one emperor is mentioned in the De Ceremoniis for 831; Constantine is also missing on coins minted in 831/32 and 832/33, though this could mean he was only raised to co-emperor in 833. He must have died by 835, since that year Theophilos was recorded as being without a male heir (Constantine's younger brother Michael III was only born in 839), a situation Theophilos attempted to rectify by marrying his infant daughter Maria to general Alexios Mosele, who shortly before this (possibly as early as 831) had been promoted to Caesar.

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