Theophanes was born in Constantinople of wealthy and noble iconodule parents: Isaac, governor of the islands of the Aegean Sea, and Theodora, of whose family nothing is known.

[1] His father died when Theophanes was three years old, and the Byzantine Emperor Constantine V (740–775) subsequently saw to the boy's education and upbringing at the imperial court.

She chose a convent on an island near Constantinople, while he entered the Polychronius Monastery, located in the district of Sigiane (Sigriano), near Cyzicus on the Asian side of the Sea of Marmara.

[1] Later, he built a monastery on his own lands on the island of Calonymus (now Calomio),[3] where he acquired a high degree of skill in transcribing manuscripts.

It seems that Theophanes had only prepared the tables, leaving vacant spaces for the proper dates, but that these had been filled out by someone else (Hugo von Hurter, Nomenclator literarius recentioris I, Innsbruck, 1903, 735).

[1] There also survives a further continuation, in six books, of the Chronicle down to the year 961 written by a number of mostly anonymous writers (called Theophanes Continuatus or Scriptores post Theophanem), who undertook the work at the instructions of Constantine Porphyrogenitus.