The third section, then, extends from the beginning of Book Seventy-two to the end of the work. Here Dio breaks away oftener than before from his servility to the Dignity of History, only to display a far more contemptible servility to his imperial masters. According to his own account he stood by and passively allowed atrocities to be multiplied about him, nor does he venture to express any forceful indignation at the performance of such deeds. Had he protested, the world's knowledge of Rome's degenerate tyrants would undoubtedly have been less complete than it now is; and Dio was quite enough of an egotist to believe that his own life and work were of paramount importance. If we compare him unfavorably with Epictetus, we must remember that the latter was obscure enough to be ignored. In both the second and the third parts, that is to say throughout the entire imperial period, Dio is conceded to have committed an error in his point of view by making the relations of the emperor to the senate the leading idea in his narrative and subordinating other events to that relation. Senator as he was, he naturally magnified its importance, and in an impartial estimate of his account one must allow for personal bias. Our historian's sources for the earlier part of his work are not positively known. He has been credited with the use of Livy, of Coelius, of Appian, and of Dionysios of Halicarnassos, but the traces are not definite enough to warrant any dogmatic assertion. Perhaps he knew Tacitus and perhaps Suetonius: the portrait of Tiberius is especially good and was probably obtained from an author of merit. But there were in existence a great multitude of books inferior or now forgotten besides the works of the authors above mentioned; and Dio's History in general shows no greater evidence of having been drawn from writers whom we know than from others whom we do not know.