5. In passing in our geographical description from Europe to Asia, the first parts of the country which present themselves are those in the northern division, and we shall therefore begin with these. Of these parts the first are those about the Tanaïs, (or Don,) which we have assumed as the boundary of Europe and Asia. These have a kind of peninsular form, for they are surrounded on the west by the river Tanaïs (or Don) and the Palus Mæotis[894] as far as the Cimmerian Bosporus,[895] and that part of the coast of the Euxine which terminates at Colchis; on the north by the Ocean, as far as the mouth of the Caspian Sea; on the east by the same sea, as far as the confines of Albania and Armenia, where the rivers Cyrus[896] and Araxes[897] empty themselves; the latter flowing through Armenia, and the Cyrus through Iberia[898] and Albania;[899] on the south is the tract of country extending from the mouth of the Cyrus as far as Colchis, and comprising about 3000 stadia from sea to sea, across the territory of the Albani, and Iberes,[900] so as to represent an isthmus.[901] Those writers do not deserve attention who contract the isthmus as much as Cleitarchus, according to whom it is subject to inundations of the sea from either side. According to Posidonius the isthmus is 1500 stadia in extent, that is, as large as the isthmus from Pelusium to the Red Sea. And I think, says he, that the isthmus between the Palus Mæotis and the Ocean is not very different from this in extent. 6. I know not how any one can rely upon his authority respecting what is uncertain, when he has nothing probable to advance on the subject; for he reasons so falsely respecting things which are evident, and this too when he enjoyed the friendship of Pompey, who had carried on war against the Iberes and Albani, and was acquainted with both the Caspian and Colchian[902] Seas on each side of the isthmus. It is related, that when Pompey[903] was at Rhodes, on his expedition against the pirates, (he was soon afterwards to carry on war against Mithridates and the nations as far as the Caspian Sea,) he accidentally heard a philosophical lecture of Posidonius; and on his departure he asked Posidonius if he had any commands; to which he replied, [CAS. 492] “To stand the first in worth, as in command.”[904] Add to this, that he wrote the history of Pompey. For these reasons he ought to have paid a greater regard to truth. 7. The second portion is that above the Hyrcanian,[905] which we also call the Caspian Sea, extending as far as the Scythians near the Indians. The third portion is continuous with the above-mentioned isthmus, and consists of the country following next in order to the isthmus and the Caspian Gates,[906] and approaching nearest the parts within the Taurus, and to Europe; these are Media, Armenia, Cappadocia, and the intervening country.[907]