Georgios Kedrenos

George Kedrenos or Cedrenus (Greek: Γεώργιος Κεδρηνός, fl. 11th century) was a Byzantine historian. In the 1050s he compiled A concise history of the world, which spanned the time from the biblical account of creation to his own day. Kedrenos is one of the few sources that discuss Khazar polities in existence after the sack of Atil in 969 (see Georgius Tzul).

...
Wikipedia