afterwards called also Gallo-Grecia, in Ancient Geography, an inland division of Asia Minor, bounded on the N. by Bithynia and Paphlagonia, E. by Pontus, S. by Cappadocia and Lycodia, W. by Phrygia. These boundaries, however, varied at different periods in the history of Galatia. The river Halys flowed in a northerly direction through the centre of the province, the eastern half of which was watered by tributaries of that stream, while the Sangarius and its affluents rose among the mountains of the western half.

According to Strabo, Galatia was occupied by three Gallic tribes: the Trocmi who dwelt in the east, the Tectosages in the centre, and the Tolstobogii in the west. Each of these tribes was subdivided into four parts; and these were each ruled over by a tetrarch of their own. The power of the tetrarchs was limited by a senate of 300, before which also all capital cases were tried. Minor offences came under the cognizance of the tetrarchs and special judges appointed by them. This system continued in force till within about fifty years B.C. The three tribes all spoke the same tongue; and though in course of time they became Hellenized, their original language was still in use among them as late as the time of Jerome.

The only towns of importance in Galatia were Tavium, the capital of the Trocmi, a small town which speedily fell into decay; Ancyra, the capital of the Tectosages, and Pesinus, the chief town of the Tolstobogii, where a splendid temple was consecrated to Agdistis, the mother of the gods. The only other place of note in Galatia was Gordium, the ancient capital of Phrygia, and the scene of Alexander's famous exploit of cutting the Gordian knot.

Galatia took its name from a body of Gauls who invaded Asia Minor about the year 279 B.C. They had formed part of the army which invaded Greece under Brennus; but having quarrelled with that commander had left his standard, and marching into Thrace under generals of their own choice, advanced to Byzantium, whence they were invited by Nicomedes, king of Bithynia, to cross into Asia and help him in his struggle against his brother Zileatus. After performing the required services, they turned their arms against their employer, and ravaged the western half of Asia Minor. Their success allured over hordes of their countrymen, who readily took service with the Asiatic kings in their wars against each other. No oriental prince was found able to check them, until Attalus king of Pergamus defeated them in a great battle B.C. 239; and compelled them to settle in that part of the country, which after them was called Galatia. They still remained independent, however, and proved a formidable foe to the Romans in their wars with Antiochus. It was found necessary to direct a special army against them, and the result of the campaign was their complete subjugation to the power of Rome. Galatia, however, was not at this time reduced to a Roman province, but the Gauls were still allowed to choose their own kings. One of the most famous of these was Deiotarus, who, in return for the assistance which he gave the Romans, was rewarded with a grant of Pontus and Armenia Minor, and styled king by the senate. On the death of his son Amyntas, B.C. 25, Galatia became a Roman province. Theodosius the Great subdivided it for purposes of government into Galatia Prima, of which Ancyra was made the capital, and Galatia Secunda, with Pesinus for its chief-town.