Strabo Geography 2.1.41

[41] Since Hipparchus does not furnish a Geography of his own, but merely reviews what is said in that of Eratosthenes, he ought to have gone farther, and corrected the whole of that writer’s mistakes. As for ourselves, it is only in those particulars where Eratosthenes is correct (and we acknowledge that he frequently errs) that we have thought it our duty to quote his own words, in order to reinstate them in their position, and to defend him when he could be acquitted of the charges of Hipparchus; never failing to break a lance with the latter writer whenever his objections seemed to be the result of a mere propensity to find fault. But when Eratosthenes is grossly mistaken, and the animadversions of Hipparchus are just, we have thought it sufficient in our Geography to set him (Eratosthenes) right by merely stating facts as they are. As the mistakes were so continual and numerous, it was better not to mention them except in a sparse and general manner. This principle in the details we shall strive to carry out. In the present instance we shall only remark, that Timosthenes, Eratosthenes, and those who preceded them, were but ill acquainted with Iberia and Keltica, ¹ and a thousand times less with Germany, Britain, and the land of the Getae and Bastarnae. ² Their want of knowledge is also great in regard to Italy, the Adriatic, the Euxine, and the countries north of these. Possibly this last remark may be regarded as captious, since Eratosthenes states, that as to distant countries, he has merely given the admeasurements as he finds them supplied by others, without vouching for their accuracy, although he sometimes adds whether the route indicated is more or less in a right line. We should not therefore subject to a too rigorous examination distances as to which no one is agreed, after the manner Hipparchus does, both in regard to the places already mentioned, and also to those of which Eratosthenes has given the distance from Hyrcania to Bactria and the countries beyond, and those from Colchis to the Sea of Hyrcania. These are points where we should not scrutinize him so narrowly as [when he describes] places situated in the heart of our continent, ³ or others equally well known; and even these should be regarded from a geographical rather than a geometrical point of view. Hipparchus, at the end of the second book of his Commentaries on the Geography of Eratosthenes, having found fault with certain statements relative to Ethiopia, tells us at the commencement of the third, that his strictures, though to a certain point geographical, will be mathematical for the most part. As for myself, I cannot find any geography there. To me it seems entirely mathematical; but Eratosthenes himself set the example; for he frequently runs into scientific speculations, having little to do with the subject in hand, and which result in vague and inexact conclusions. Thus he is a mathematician in geography, and in mathematics a geographer; and so lies open to the attacks of both parties. In this third book, both he and Timosthenes get such severe justice, that there seems nothing left for us to do; Hipparchus is quite enough.