From court to cloister
Theophanes belonged to the wealthy and well-connected aristocracy of eighth-century Constantinople. According to the accounts of his life, his father held a governing office and had ties to the imperial family, and after his early death the future saint was educated under the care of the court during the reign of Constantine V. He rose to a position of dignity in the service of the empire.
His turn to monasticism was gradual and shared. Though his rank obliged him to marry, he is said to have persuaded his wife to live in continence, and when her father died the two separated by agreement to pursue the religious life. His wife entered a convent, and Theophanes joined a monastery in the region of Cyzicus before establishing his own communities.
Abbot and founder
Theophanes first established a monastery on an island in the Sea of Marmara, where he is remembered for his diligence in copying manuscripts. He afterward returned to the district of Sigriane in Asia Minor and founded the monastery that gave him his customary title — the Great Acre, or Megas Agros — over which he presided as abbot.
It was as abbot that he took part in the Second Council of Nicaea in 787, lending his name to the council's restoration of the veneration of icons. His monastic foundations and his standing as a confessor of the icons anchored his reputation in his own day, before his chronicle secured his memory for later generations.
Confessor of the icons
The second outbreak of imperial iconoclasm under Leo V the Armenian brought Theophanes into open conflict with the throne. Summoned to Constantinople and pressed to renounce the icons, he refused and was imprisoned and harshly treated for about two years. On his release he was sent into exile on the island of Samothrace, where he died soon afterward, his health broken by his sufferings.
This steadfastness under persecution is the reason he is venerated with the title 'Confessor' rather than as a simple monastic saint. The synaxarion accounts relate that his monastery was later restored and his relics translated back to it.
The Chronographia
At the request of George Syncellus, who had begun a chronicle and entrusted its continuation to him, Theophanes composed the Chronographia, a year-by-year chronicle extending from the late third century to the early ninth (covering roughly the years 284-813). The work draws together earlier sources and is organized by an elaborate chronological framework.
The Chronographia became one of the most valuable surviving sources for the history of the Byzantine world in this period, and it preserves information not found elsewhere. It is for this work, as much as for his monastic life, that Theophanes is known to historians.