The proof of the value of the work of Herodotus is found in the fact that it has come down to us entire in numerous copies, something that can be said of only three or four other considerable historical compositions of the entire classical period; two others of this select company being Thucydides and Xenophon, both of whom were contemporaries of Herodotus, though considerably younger, and therefore, properly enough, counted as belonging to the next generation. Of the other Greek historians, the biographical works of Plutarch, the works of Strabo and Pausanius, which are geographical rather than strictly historical, and the _Life of Alexander the Great_ by Arrian, are the sole ones of the large number undoubtedly written that have come down to us intact. A survey of the Roman historians furnishes an even more striking illustration, for here no one of the great historical works has been preserved in its entirety. Livy’s monumental work is entire as to the earlier books, which treat of the mythical and half-mythical period of Roman development; but the parts of it that treated of later Roman history, concerning which the author could have spoken, and probably did speak, with first-hand knowledge, are almost entirely lost. In other words, the copyists of the middle ages preserved the least valuable portion of Livy, doubtless because they found the hero tales of mythical Rome more interesting than the matter-of-fact recitals of the events of the later republic and the early empire. We can hardly suppose that Livy detailed the events of the later period with less art than characterised his earlier work, but different conditions were imposed upon him. He had now to deal with much fuller records than hitherto, and no doubt he treated many subjects that seemed important to him, simply because they were near at hand, but which another generation found tiresome and not worth the trouble of copying. Thus we see emphasised again the salient point that the interesting story rather than the important historical narrative proved itself most fit for preservation in the estimate of posterity. Of the other great historians of Rome, Tacitus, Dionysius, Dion Cassius, Polybius, have all fared rather worse than Livy, although a few briefer masterpieces, like the two histories of Sallust and the _Gallic Wars_ of Cæsar, and such biographies as the “Lives” of Suetonius and Cornelius Nepos, were able to fight their way through the middle ages and gain the safe shelter of the printing-press without material loss.