Gallic invasion of the Balkans in the context of "Western Balkans"

Galatia (/ɡəˈleɪʃə/; Ancient Greek: Γαλατία, Galatía) was an ancient area in the highlands of central Anatolia, roughly corresponding to the provinces of Ankara and Eskişehir in modern Turkey. Galatia was named after the Gauls from Thrace (cf. Tylis), who settled here and became a small transient foreign tribe in the 3rd century BC, following the Gallic invasion of the Balkans in 279 BC. It has been called the "Gallia" of the East, "Gallacia" ultimately deriving from the northwest of ancient Spain.

The Gauls (Latin: Galli; Ancient Greek: Γαλάται, Galátai) were a group of Celtic peoples of mainland Europe in the Iron Age and the Roman period (roughly 5th century BC to 5th century AD). Their homeland was known as Gaul (Gallia). They spoke Gaulish, a continental Celtic language.

The Gauls emerged around the 5th century BC as bearers of La Tène culture north and west of the Alps. By the 4th century BC, they were spread over much of what is now France, Belgium, Switzerland, Southern Germany, Austria, and the Czech Republic, by virtue of controlling the trade routes along the river systems of the Rhône, Seine, Rhine, and Danube. They reached the peak of their power in the 3rd century BC. During the 4th and 3rd centuries BC, the Gauls expanded into Northern Italy (Cisalpine Gaul), leading to the Roman–Gallic wars, and into the Balkans, leading to war with the Greeks. These latter Gauls eventually settled in Anatolia (contemporary Turkey), becoming known as Galatians.

Singidunum (Serbian: Сингидунум, Singidunum) was an ancient city which later evolved into modern Belgrade, the capital of Serbia. The name is of Celtic origin, going back to the time when the Celtic tribe Scordisci settled the area in the 3rd century BC, following the Gallic invasion of the Balkans. Later on, the Roman Republic conquered the area in 75 BC and incorporated it into the province of Moesia. It was an important fort of the Danubian Limes and Roman Legio IV Flavia Felix was garrisoned there since 86 AD. Singidunum was the birthplace of the Roman Emperor Jovian. It was sacked by Huns in 441, and by Avars and Slavs in 584. At the beginning of the 7th century, the Singidunum fort was finally destroyed.

A large part of Belgrade's downtown belongs to the "Archaeological Site of Singidunum", which was declared a protected zone on 30 June 1964.

The Battle of Thermopylae was fought in 279 BC between invading Gallic armies and a combined army of Greek Aetolians, Boeotians, Athenians, and Phocians at Thermopylae. The Gauls under Brennus were victorious, and advanced further into the Greek peninsula where they attempted to sack Delphi but were completely defeated.

Brennus (or Brennos) (died 279 BC at Delphi, Ancient Greece) was one of the Gaulish leaders of the army of the Gallic invasion of the Balkans. While invading the Greek mainland he managed to momentarily reach as far south as Delphi in an attempt to loot the rich treasury of the sanctuary of Apollo. His army suffered a devastating defeat at Delphi; he was heavily injured during the battle and committed suicide there. His army was forced to a continuous retreat by the tactical attacks of the Greek city-states and was cut down to a remaining band that fled from Greece.

In 280 BC a great army, comprising about 85,000 warriors, coming from Pannonia and split in three divisions, marched south in a 'great expedition' to the Greek mainland against Macedonia and then further south to central Greece as far south as Delphi during a failed and short-lived campaign against the Greek city-states. The division led by Brennus and Acichorius moved against the Paionians.

Bolgios (Greek: Βόλγιος, also Bolgius, Belgius) was a Gaulish leader during the Gallic invasion of the Balkans who led an invasion of Macedon and Illyria in 279 BC, killing the Macedonian king Ptolemy Keraunos.

He was part of a force of Gauls settled in Pannonia who had advanced to Thrace under a leader called Cambaules. Deciding on fresh conquests, they sent separate forces to different regions: one led by Cerethrius against the Thracians and Triballi; another against Paionia led by Brennus and Acichorius; and a third against the Macedonians and Illyrians, led by Bolgios.