THE GALATIANS, WHO WERE THEY?

Ancient Galatia was an area in the highlands of central Anatolia in modern Turkey. It was bounded on the North by Bithynia and Paphlagonia, on the Easy by Pontus and cappadocia, on the South by Cilicia and Lycaonia, and on the West by Phrygia. Its capital was Ancyra (today Ankara, Turkey).
Galatia was named for the immigrant Gauls from Thrace, a region bounded by the Balkan Mountains on the North, Rhodope Mountains and the Aegean Sea on the South, and the Black Sea and the Sea of Marmara on the East.
The 3 Celtic tribes that enter Anatolia as a contingent of Celtic raiders from the Danube Region, and settled in those Regions of Phyrgia were the Tecto-Sages, Tol-isto-bogii and Trocmi.
The Tecto-Sages came originally from the region around Toulouse in Gaul, present-day the capital city of the SouthWestern French Department of Haute-Garonne, as well as of the Midi-Pyrenees Region. It lies on the banks of the Garonne River, 150km/93mi from the Mediterranea Sea, 230km/143mi from the Atlantic Ocean, and 680km/420mi from Paris. The Toulouse metropolitan area is the 4th largest in France, after Paris and Marseille.
During the late period of the 2rd century BC, a great Celtic migration in which the 3 Tribes formed part of the Tribal Confederation of the Volcae, invaded Macedon in 270BC and defeated the assembled Greeks at the Battle of Thermo-Pylae in 279 BC. Immediately after, tribes known by the name Volcae were found simultaneously in Southern Gaul, Moravia, the Ebro River Valley of Iberia, and Galatia in Asia Minor.
The tribe of the Tol-isto-boggi appeared as part of the troops in the army of Brennus on its way to plunder Delphi in Greece in 279 BC. In Dardania , it is said, some 20,000 men under Leonorius and Lutarius, seceded from Brennus and entered Thrace, where they collected tribute from the Region, including Byzantium. Subsequently they group, crossed the Hellespont to fight as mercenaries for Nicomedes I of Bithynia, who wanted their help in a Dynastic struggle against his brother. Then they left Bithynia to plunder Anatolia. The Tol-isto-bogii received Aeolia and Ionia as territory. For a greater part of their centuries-long stay in Galatia, the Tol-isto-bogii were located in what is now Eskisehir Province just West of Ankara.
Driven by highly mobile groups operating outside the Tribal System and comprising diverse element, the Volcae were one of the new ethnic entities formed during the Celtic military expansion at the beginning of the 3rd century.
The 3 tribes who formed the Galatian people used the term "sept" to make a distintcion from the rest of the Celts, especially of  Scottish or Irish background. The word derive from the Latin "saeptum" meaning "enclosure" or "fold" or "sect," as a manner to distinguidh one group from another.
In 189 BC, all three tribes were beaten by the Roman Consul Gnaeus Manlius Vulso in the Battles of Mt. Olympus and Mt. Magaba.
In the constitution of the Galatian State: by custom, each tribe was divided into cantons, each governed by a chief (tetrarch) followed by a judge, whose powers were unlimited except in cases of murder, which were tried before a council of 300 drawn from the 12 cantons and meeting at a "holy place of an Oak Grove." The Galatian arrivals left the local population of Cappadocians in control of the towns and most of the land, paying tithes to their new overlords, who formed a "military aristocracy" and kept aloof in fortified farmsteads, surrounded by their bands.
These "Celtic Warriors" were respected by Greeks and Romans. They were often hired as mercenaries soldiers,  fighting on both sides in the great battles of the times. For years, the chieftains and their bands ravaged the Western half of Asia Minor, as allies of one or other of the warring princes, without any serious check. The King of Attalid Perg-Amon hired Galatians in the incresingly devastating wars of Asia Minor. One of the tribes in his service, the Agio-Sages, refused to obey after a lunar eclipse on 1st September 218BC. Another band deserted from their Egyptian overlord Ptolemy IV (reigned 221-204 BC) after a solar eclipse had broken their spirits. This ended when they sided with the renegade Seleucid prince Anti-Ochus Hierax ruling in Asia Minor, who tried to defeat At-Talus, the ruler of Perg-Amon (241-197 BC). In 189 BC, all 3 Tribes were beaten by the Roman Consul Gnaeus Manlius Vulso. Roma  dominated Galatia through Regional Rulers from 189 onward. Galacia declined under Pontic ascendancy. The 3 Celtic tribes remained as described: -the Tecto-Sages in the centre, roundtheir capital Ankara. -the Tol-Isto-Bogii on the West, round Pessinus as their chief town, sacred to Cybele. -the Trocmi on the East, round their chief town Tavium. They were finally freed by th Mithridatic Wars of 88-63 BC. during which they supported Rome.
In Pompey's administrative settlement of 64BC, Galatia formally became a client-state of the Roman Empire. The Old Constitution disappeared, and 3 chiefs were appointed, one for each tribe. But this arrangement soon gave way o the ambition of one of the chieftains, Dei-Otarus, the contemporary of Cicero and Julius Caesar, who made himself Master of the other two and was finally recognized by the Romans as "King" of Galatia. Upon his death, the Kingdom was given to Amyntas, an auxiliary commander in the Roman army of Brutus and Cassius who gained the favor of Mark Antony. After his death in 25 BC, Galatia was incorporated by Augustus into the Roman Empire, becoming a Roman Province. Near his capital Ancyra (Ankara), Pylamenes, the king's heir, rebuilt a temple of the Phrygian god Men to venerate Augustus (the Monumentum Ancyranum), as a sign of fidelity. It was on the walls of this temple in Galatia that the major source for the "Deeds of the Divine Augustus" portrayed to the Roman People. It was the base of the establisment of the Julio-Claudian Dynasty that was to follow Augustus. Few of the provinces proved more enthusiastically loyal to Rome.
The fate of the Galatians is a subject of some uncertainty, but they seem to have been absorved into the Greek-speaking populations of Anatolia.