On Bithynia

When Rome got involved in war with Philip V of Macedon and his son Perseus, the kingdom of Bithynia covered an area of 18 thousand square miles in the northwestern corner of Asia Minor -- approximately the size of Denmark today. From the Pontus Euxinus south to the Mysian Mt. Olympus, from the shores of the Propontis and the Bosporus to the river Rhyndacus which would become the border of the future Roman province of Asia, the kingdom stretched eastward to the mountain ranges that form the wall of the plains of Anatolia, the region called Paphlagonia. On the coast of the Pontus Euxinus it stretched as far east as the free city of Herakleia.

The one great river of Bithynia is the Sangarius that describes a winding course eastward from the temple-city of Pessinus, then northward, then westward, entering Bithynia in the southeastern corner. It forces its way through the mountain range around Mt. Olympus, past several gorges and goes north to empty into the Pontus Euxinus. The broad basin of its lower course forms the largest and most beautiful Bithynian plain, abounding in grain and fruit.

This same lower course is navigable for a short distance. It divides Bithynia into two sections : the hill-country on the west, along the coast of the Propontis, deeply indented by the Gulf of Nicomedia, and including Lake Ascania and the major coastal cities of Bithynia -- the Euxine coast has no harbours of great importance ; and the towering mountainous region east of the Sangarius, broken only by tiny plains. Through this rugged country extend the magnificent forests of firs, oaks and beeches. Beyond these mountains, to the east, are the plain of the upper Hypius and, still further east, the cities of Prusias and Bithynium (later called Claudiopolis).

The region called Bithynia, separated from Europe only by the narrow straits of the Bosporus, had been invaded and colonised from earliest times by Thracian tribes migrating east and south. Greeks from Megara establishd themselves along the Bosporus (Byzantium and Chalcedon) and along the Pontus Euxinus. Ionian invaders founded cities along the Propontis. These small settlements left the interior country largely unaffected by Greek culture for centuries.

From David Magie, Roman Rule in Asia Minor to the End of the Third Century After Christ, vol. I, Princeton, 1950, pp. 302 - 304.