In this research, I shall attempt, through a perusal of some of the ancient sources and through reading some of the theories of modern historians, to attain a better understanding of the personality and reign of the emperor Gaius, commonly known as Caligula. To this end, my focus will be on the writings of Cassius Dio. At the same time, I shall discuss of the life of Marcus Julius Agrippa I and his relationship to Gaius, and show how an understanding of Agrippa and his relationship with Gaius might also throw some light on the personality and reign of Caesar Caligula.