Constantine

Symbatios (, from the Armenian Սմբատ), variously also Sabbatios (Σαββάτιος; Sabbátios) or Sambates (Σαμβάτης; Sambatēs) in some sources,

At the head of a military revolt following the disastrous Battle of Versinikia against the Bulgars, Leo deposed Michael I on 11 July 813 and was crowned emperor on the next day. Some time after he had Symbatios crowned co-emperor and renamed Constantine. The latter name was not chosen randomly: aside from it being a traditional Byzantine imperial name dating back to Constantine the Great, the assembled troops now publicly acclaimed the emperors "Leo and Constantine", evoking openly the iconoclast emperor Leo III the Isaurian and his son Constantine V .

Although prior to his accession Leo had given written guarantees to the iconophile patriarch Nikephoros I that he would not attempt to overthrow iconophile church doctrine, the naming of the new co-emperor was a clear statement of intent to the contrary. Leo's motivations can only be guessed at, but at a time when the environs of Constantinople itself were being raided by the Bulgar ruler Krum, the military successes achieved by the iconoclast emperors contrasted starkly with the defeats suffered by the recent iconophile regimes. Leo was also a military man, and the memory of the iconoclast emperors was particularly cherished by the army, where many still adhered to iconoclasm.

On 14 March 814, Leo forced the resignation of Patriarch Nikephoros I, and appointed the pro-iconoclast Theodotos Melissenos, the son of one of Constantine V's brothers-in-law, in his place. The new patriarch convened a Church council in Constantinople, which overturned the Second Council of Nicaea and reinstated the ban on the veneration of icons. The council was presided over by Theodotos, while Constantine attended it as his father's representative. In 819/820, he issued, jointly with his father, a novel on marriage law.

Leo the Armenian was assassinated on 25 December 820 by the supporters of Michael the Amorian, who had been imprisoned for conspiring against Leo. Michael was released from prison and proclaimed emperor on the same night. The new emperor banished Constantine, along with his mother and three brothers, Basil, Gregory, and Theodosios, to the island of Prote, one of the Princes' Islands in the Sea of Marmara. There, the four brothers were castrated to make them incapable of future claims for the throne, and tonsured. As monks there they would live out their lives that that of their servants on the allowance from their confiscated estates granted by Michael the Amorian. Basil and Gregory continued as iconophiles as late as 847, but nothing further is known of Constantine.