Lucius (or Claudius) Cassius Dio, known in English as Cassius Dio, Dio Cassius, or Dio, was a Roman consul and noted historian who published a history of Rome in 80 volumes (written in Greek). The entire period covered by Dio’s work is approximately 1,400 years. Of the 80 books, written over 22 years, many survive into the modern age, intact, or as fragments, providing modern scholars with a detailed perspective on Roman history.