death he came to Rome, apparently about the year 180. In describing the behaviour of Commodus toward the senate and others at the beginning of his reign, he states that his account is henceforth the result of personal observation and not hearsay. It seems a reasonable inference, therefore, that he was already a member of the senate at this time, and therefore at least twenty-five years of age. Pertinax in 193 nominated him to the praetorship for the following year;[1] but in the meantime both Pertinax and his successor Julianus were overthrown, and Dio thus assumed the office under Septimius Severus. The mild course of the new ruler at the outset of his reign, taken in connexion with his past record, was such as to win the enthusiastic admiration of Dio and to encourage in him the hope that a new era was now dawning.
It was at this point, apparently, that Dio's literary work began. He wrote and published a little book, as he tells us,[2] containing an account of the dreams and portents which had foretold to Severus his future greatness.[3] The details he had doubtless learned from the emperor himself, and he presumably had implicit faith in all these signs, to judge from his fondness for reporting omens and prodigies in general. Upon receiving a gracious letter from Severus in acknowledgment of a presentation copy, he seemed to be admonished by a dream the following night to
