Theophanes (c. 758/60-817/8) wrote the Chronicle in Greek
during the years 810-815 CE as a continuation of George Syncellus'
Chronicle. Theophanes' Chronicle
covers the period from 284 CE, where the Chronicle of George Synkellos ends, until 813 CE
Theophanes explains that George had asked him to complete the task of compiling the history and had given Theophanes the
materials he had gathered. Neville (2018:61)
describes Theophanes' Chronicle as follows:
It is one of few Byzantine texts that is a true chronicle, in that it enumerates
every year, and lists events for each year. The entry for each year begins with
a listing of the year of the world, the year since the Incarnation, the regnal
year of the Roman Emperor, the Persian Emperor, and the bishops of Rome,
Constantinople, Jerusalem, Alexandria, and Antioch. After the conquest of
the Persian Empire, it uses years of the rulers of the Arabs in place of the
Persian Emperors. Despite the impression of chronological accuracy, many
of these dates are mistaken. Scholars also debate whether these dates were
integral to Theophanes’ original Chronicle or were added by a later copyist.
Mango and Scott (1997:xci)
characterize Theophanes' Chronicle as a "file" of sources and list at least 17 sources which informed his Chronicle
(Mango and Scott, 1997:lxxiv-lxxxii).
Hoyland (2011:10) noted that Theophanes made extensive use of an
"eastern source" for events in Muslim-ruled lands during the the time period of the 630s-740s and continued to
narrate events occurring in
Muslim-ruled lands, until ca. 780 either making
use of another chronicle
for these three decades or, more likely,  had at his disposal a continuation of the ‘eastern source’. Theophanes' ‘eastern source’
has been the source of much scholarly investigation and debate.