The power of the empire of the Seleucidæ went on increasing until the time when the Romans seized upon it. Extending from the Mediterranean to the Oxus and Caucasus, this empire was composed of nearly all the provinces of the ancient kingdom of the Persians, and included peoples of different origins.[407] Media was fertile, and its capital, Ecbatana, which Polybius represents as excelling in riches and the incredible luxury of its palaces the other cities of Asia, had not yet been despoiled by Antiochus III.;[408] Babylonia, once the seat of a powerful empire, and Phœnicia, long the most commercial country in the world, made part of Syria, and touched upon the frontiers of the Parthians. Caravans, following a route which has remained the same during many centuries, placed Syria in communication with Arabia,[409] whence came ebony, ivory, perfumes, resins, and spices; the Syrian ports were the intermediate marts for the merchants who proceeded as far as India, where Seleucus I. went to conclude a treaty with Sandrocottus. The merchandise of this country ascended the Euphrates as far as Thapsacus, and thence it was exported to all the provinces.[410] Communications so distant and multiplied explain the prosperity of the empire of the Seleucidæ. Babylonia competed with Phrygia in embroidered tissues; purple and the tissues of Tyre, the glass, goldsmiths’ work, and dyes of Sidon, were exported far. Commerce had penetrated to the extremities of Asia. Silk stuffs were sent from the frontiers of China to Caspiæ Portæ, and thence conveyed by caravans at once towards the Tyrian Sea, Mesopotamia, and Pontus.[411] Subsequently, the invasion of the Parthians, by intercepting the routes, prevented the Greeks from penetrating into the heart of Asia. Hence Seleucus Nicator formed the project of opening a way of direct communication between Greece and Bactriana, by constructing a canal from the Black Sea to the Caspian Sea.[412] Mines of precious metals were rather rare in Syria; but there was abundance of gold and silver, introduced by the Phœnicians, or imported from Arabia or Central Asia. We may judge of the abundance of money possessed by Seleucia, on the Tigris, by the amount of the contribution which was extorted from it by Antiochus III. (a thousand talents).[413] The sums which the Syrian monarchs engaged to pay to the Romans were immense.[414] The soil gave produce equal in importance with that of industry.[415] Susiana, one of the provinces of Persia which had fallen under the dominion of the Seleucidæ, had so great a reputation for its corn, that Egypt alone could compete with it.[416] Cœle-Syria was, like the north of Mesopotamia, in repute for its cattle.[417] Palestine furnished abundance of wheat, oil, and wine. The condition of Syria was still so prosperous in the seventh century of Rome, that the philosopher Posidonius represents its inhabitants as indulging in continual festivals, and dividing their time between the labours of the field, banquets, and the exercises of the gymnasium.[418] The festivals of Antiochus IV., in the town of Daphne,[419] give a notion of the extravagance displayed by the grandees of that country.