MYSIA, in ancient geography, was the name given to a province in the north - west of Asia Minor, which was bounded by Lydia and Phrygia on the S., by Bithynia on the N.E., and by the Propontis and iEgean Sea Mysia under the name of the Troad, a district which was the boundary between the two, but on this subject also there was much discrepancy among ancient geographers.

The physical geography of Mysia (considered apart from that of the Troad) is characterized by two mountain-chains : that of Olympus in the north, which may be regarded as constituting the boundary between Mysia and Bithynia, and rises to a height of more than 6000 feet ; and that of Temnus in the south, which for some distance separates Mysia from Lydia, and is afterwards prolonged through the former province to the neighbourhood of the Gulf of Adramyttium. The only considerable rivers are the Rhyndacus and its tributary the Macestus in the northern part of the province, both of which have their sources in the high tableland of Phrygia, and, after diverging widely in their course through Mysia, ultimately unite their waters below the Lake of Apollonia at a distance of only about 15 miles from the Propontis. The Caicus in the south takes its rise in Mount Temnus, and from thence flows westward to the 2Egean Sea, passing within a few miles of the city of Pergamum, and discharging its waters into the Elaitic Gulf. In the northern portion of the province are two considerable lakes : that of Apollonia, formed by the expansion of the waters of the Rhyndacus, and nearly 50 miles in circumference ; and that of Miletopolis, about 30 miles round, the waters of which are discharged into the Macestus.

The most important cities of Mysia were Pergamum in the valley of the Caicus, about 20 miles from the sea, which under the successors of Alexander became the seat of a flourishing Greek monarchy (see PERGAMIIM), and Cyzicus on the shores of the Propontis, a Milesian colony, which attained to a high degree of wealth and prosperity. But the whole of the sea-coast from thence round to the Gulf of Adramyttium was studded with a series of Greek towns, extending along the south shore of the Propontis, as well as the Hellespont and the Troad, several of which were places of considerable importance, including Parium, Lampsacus, and Abydos. In like manner the whole seacoast from the Gulf of Adramyttium to the mouth of the Caicus, and from thence to the Elaitic Gulf, was occupied by Greek colonies, many of them dating from a very early period, and for the most part of 2Eolian origin, from which circumstance the whole of this coast district was known by the name of lEolis, as the corresponding district between Lydia and the sea was called Ionia (2Eoms). The most considerable of these Greek towns were Assos and Adramyttium, on the gulf that derived its name from the latter city, and farther south, on the Elaitic Gulf, Elma, Myrina, and Cyme.

Ancient writers all agree in describing the Mysians as a distinct people, like their neighbours the Lydians and Phrygians, though they never appear in history as an independent nation. Their ethnological relations, like those of the other tribes of western Asia, are rather obscure ; but it appears from Herodotus and Strabo that they were a kindred race with the Lydians and Carians, a fact attested by their common participation in the sacred rites at the great temple of Zeus at Labranda, as well as by the statement of the historian Xanthus of Lydia (a competent authority upon such a point) that their language was a mixture of Lydian and Phrygian. Strabo was of opinion that they came originally from Thrace, and were a branch of the same people as the Mysians or Msialis who dwelt on the banks of the Danube, - a view not inconsistent with the preceding, as he considered the Phrygians and Lydians also as having migrated from Europe into Asia. According to a Carian tradition reported by Herodotus (i. 171) Lydus and Mysus were brothers of Car, - an idea which also points to the belief in a common origin of the three nations. The Mysians appear in the list of the Trojan allies in Homer ; but nothing else is known of their early history. The story told by Herodotus (vii. 20) of their having invaded Europe in conjunction with the Teucrians before the Trojan War is probably a mere fiction ; and the first historical fact we learn concerning them is their subjugation, together with all the surrounding nations, by the Lydian king Crcesus. After the fall of the Lydian monarchy they naturally passed under the Persian empire, and so continued until its overthrow by Alexander. After the death of the conqueror they were annexed to the Syrian monarchy, of which they continued to form a part until the defeat of Antiochus the Great (190 B.c.), after which they were transferred by the Romans to the dominion of Eumenes, king of Pergamum, as a reward for his services during the war. After the extinction of the Pergamenian dynasty (130 B.c.) Mysia became a part of the Roman province of Asia, and from this time disappears from history. The inhabitants probably became gradually Hellenized, but none of the towns of the interior, except Pergamum, ever attained to any importance.

The only relic of the Mysian language is a very short inscription found by Mr Frank Calvert in the acropolis of Thymbria, and supposed by Professor Sayce to be in the Mysian dialect, but its evidence is very inconclusive.