Theophylact (son of Michael I)

Theophylact
Co-emperor of the Byzantine Empire
Gold solidus of Michael I, with Theophylact on the reverse
Reign	25 December 811 – 11 July 813 (alongside Michael I Rhangabe)
Predecessor	Michael I Rangabe
Successor	Leo V the Armenian
Born	ca. 793 Constantinople
Died	15 January 849
Dynasty	Nikephorian dynasty
Father	Michael I Rangabe
Mother	Prokopia

Theophylact or Theophylaktos (Greek: Θεοφύλακτος) was the eldest son of the Byzantine emperor Michael I Rhangabe (r. 811–813) and grandson, on his mother's side, of Nikephoros I (r. 802–811). He was junior co-emperor alongside his father for the duration of the latter's reign, and was tonsured, castrated, and exiled to Plate Island after his overthrow.

Theophylact was born to Michael Rhangabe and Prokopia circa 793. He was the couple's second child after his sister Gorgo, and was named after his paternal grandfather, the droungarios of the Dodekanesos Theophylact Rhangabe, who had participated in a failed conspiracy to wrest the throne from Empress-regent Irene of Athens in 780. His maternal grandfather, Nikephoros Ι, was a staunch supporter of Irene and would soon rise to become her General Logothete (finance minister), eventually to depose her in October 802.

Following the death of Nikephoros Ι in the Battle of Pliska on 26 July 811 and the crippling of his only son and heir Staurakios in the same battle, on 2 October the court acclaimed Nikephoros's son-in-law Michael Rhangabe as emperor and forced Staurakios to abdicate. Michael immediately set about to consolidate his rule, distributing lavish gifts, crowning his wife as Augusta on 12 October, and finally, raising Theophylact – then aged eighteen – to the position of co-emperor on Christmas Day, 25 December 811. At about the same time, Michael sent an embassy under Bishop Michael of Synnada to the Frankish court, which among other issues raised the prospect of an imperial marriage between Theophylact and one of Charlemagne's daughters. Despite a warm reception at Aachen, however, Charlemagne hesitated to agree to such a match.