As we pass from Europe to Asia in our geography, the northern division is the first of the two divisions to which we come; and therefore we must begin with this. Of this division the first portion is that in the region of the Tanaïs River, which I have taken as the boundary between Europe and Asia. This portion forms, in a way, a peninsula, for it is surrounded on the west by the Tanaïs River and Lake Maeotis as far as the Bosporus1
and that part of the coast of the Euxine Sea which terminates at Colchis; and then on the north by the Ocean as far as the mouth of the Caspian Sea;2
and then on the east by this same sea as far as the boundary between Albania and Armenia, where empty the rivers Cyrus and Araxes, the Araxes flowing through Armenia and the Cyrus through Iberia and Albania; and lastly, on the south by the tract of country which extends from the outlet of the Cyrus River to Colchis, which is about three thousand stadia from sea to sea, across the territory of the Albanians and the Iberians, and therefore is described as an isthmus. But those writers who have reduced the width of the isthmus as much as Cleitarchus3
has, who says that it is subject to inundation from either sea, should not be considered even worthy of mention. Poseidonius states that the isthmus is fifteen hundred stadia across, as wide as the isthmus from Pelusium to the Red Sea.4
"And in my opinion," he says, "the isthmus from Lake Maeotis to the Ocean does not differ much therefrom."