The rich pastures of Media and Armenia furnished excellent horses.

Bactria gave an inexhaustible supply of camels.

Elephants in large numbers were readily procurable from India.

Gold, silver, copper, iron, lead, tin, were furnished by several of the provinces, and precious stones of various kinds abounded.

Moreover, for above ten centuries, the precious metals and the most valuable kinds of merchandise had flowed from every quarter into the region; and though the Macedonians may have carried off, or wasted, a considerable quantity of both, yet the accumulations of ages withstood the drain, and the hoarded wealth which had come down from Assyrian, Babylonian, and Median times was to be found in the days of Seleucus chiefly within the limits of his Empire.
The situation which nature pointed out as most suitable for the capital of a kingdom having the extension that has been here indicated was some portion of the Mesopotamian valley, which was at once central and fertile.