Lachmann[980] has satisfactorily shown that the assertions of Livy are not based upon personal investigation, but that he trusted to the annalists, and took advantage of the researches of preceding historians. This is all that he himself professes to do; and even these professions he does not always satisfactorily perform. He does not appear to have profited by the Annals of Varro or the _Origines_ of Cato, a work which, according to the testimony of Cicero, must have been invaluable to an historian; and although the Archæologia of Dionysius were published about the time at which Livy commenced his history,[981] there is no evidence that he makes use of it; certainly he never acknowledges any obligation to the indefatigable researches of the Greek historian. According to his own confession,[982] Roman history is total darkness until the capture of Rome by the Gauls; and although a dim light then begins to break, a twilight period succeeds, which continues until the first Punic war. But it cannot be asserted that he prepared himself for his difficult task as he ought, or took advantage of all the means at his disposal to enlighten the obscurity in which his subject was involved. The authorities on which he principally depends for the contents of the first Decade were such as Ennius, Fab. Pictor, Cincius, and Piso. It is evident that he also consulted Greek writers. In the third, which contains the most beautiful and elaborate passages of the whole work, he follows Polybius. Nor could he, in this portion of his history, follow a safer one. The Romans, notwithstanding all their practical tendencies, did little to promote geographical science. It is amongst the Greeks that we find the most accurate and indefatigable geographers, such as were Polybius, Strabo, and Ptolemy.