Strabo Geography 1.2.1

[1] No one can [justly] blame us for having undertaken to write on a subject already often treated of, unless it appears that we have done nothing more than copy the works of former writers. In our opinion, though they may have perfectly treated some subjects, in others they have still left much to be completed; and we shall be justified in our performance, if we can add to their information even in a trifling degree. At the present moment the conquests of the Romans and Parthians have added much to our knowledge, which (as was well observed by Eratosthenes) had been considerably increased by the expedition of Alexander. This prince laid open to our view the greater part of Asia, and the whole north of Europe as far as the Danube. And the Romans [have discovered to us] the entire west of Europe as far as the river Elbe, which divides Germany, and the country beyond the Ister to the river Dniester. The country beyond this to the Maeotis, ¹ and the coasts extending along Colchis, ² was brought to light by Mithridates, surnamed Eupator, and his generals. To the Parthians we are indebted for a better acquaintance with Hyrcania, ³ Bactriana, ⁴ and the land of the Scythians ⁵ lying beyond, of which before we knew but little. Thus we can add much information not supplied by former writers, but this will best be seen when we come to treat on the writers who have preceded us; and this method we shall pursue, not so much in regard to the primitive geographers, as to Eratosthenes and those subsequent to him. As these writers far surpassed the generality in the amount of their knowledge, so naturally it is more difficult to detect their errors when such occur. If I seem to contradict those most whom I take chiefly for my guides, I must claim indulgence on the plea, that it was never intended to criticise the whole body of geographers, the larger number of whom are not worthy of consideration, but to give an opinion of those only who are generally found correct. Still, while many are beneath discussion, such men as Eratosthenes, Posidonius, Hipparchus, Polybius, and others of their stamp, deserve our highest consideration.