Celtic Invasion of Greece (279 BC): Brennus Attacks Delphi

The Celtic invasion of Greece was a large migration and raid by Gallic warriors who swept through Macedonia and into central Greece in 280-279 BC. Led by a chieftain the Greeks called Brennus, the main army forced its way past Thermopylae and attacked the sanctuary of Apollo at Delphi in the winter of 279/278 BC, before being driven back with heavy losses. The episode shook the Hellenistic world and led directly to the settlement of Celts in Anatolia.

Background

By the early 3rd century BC, Celtic groups had moved down the Danube and settled in the central Balkans. Their arrival coincided with chaos in Macedonia, where the successors of Alexander the Great were fighting over his empire in the wars of the Diadochi. In 281 BC Ptolemy Keraunos murdered Seleucus I and seized the Macedonian throne, but his kingdom was weak and divided.

In 280/279 BC a Gallic force under Bolgius invaded Macedonia. Ptolemy Keraunos met them in battle, was defeated, captured and beheaded. Macedonia fell into disorder, and a general named Sosthenes managed only a limited defence.

The invasion of Greece

In 279 BC a much larger army led by Brennus and Acichorius crossed Macedonia and headed south. Pausanias gives it 152,000 infantry and 20,400 cavalry; modern historians regard such numbers as greatly exaggerated, but it was clearly a very large force, accompanied by wagons and families.

The Greek states assembled an allied army at Thermopylae, the narrow coastal pass where Leonidas had fought the Persians two centuries earlier, in 480 BC. The Athenian contingent under Callippus played a leading role, with Boeotians, Phocians, Aetolians and others. The Gauls failed to break through head-on. Brennus then sent a force into Aetolia, where it sacked the town of Callium with great brutality, drawing the Aetolian troops home.

Finally, local guides led the Gauls over the mountain path, the Anopaea, that the Persians had used in 480 BC. The Greek defenders escaped by sea on Athenian ships, and the road to Delphi lay open.

The attack on Delphi

Delphi was the most famous religious site in Greece, rich with offerings from cities and kings over centuries at the Oracle of Delphi. Its defenders, mostly Phocians and Aetolians, held the steep slopes above the sanctuary.

Ancient accounts describe a battle fought in bitter winter weather. An earthquake, thunder, a snowstorm and rockfalls from Mount Parnassus struck the attackers, and Greek writers credited Apollo himself, with apparitions of heroes, for the victory. The Gauls were thrown back, and Brennus was wounded. According to Pausanias he later killed himself, and his army suffered heavily from cold, hunger and pursuit during its retreat north.

Aftermath

The defeat did not end the Gallic presence in the region. In 277 BC Antigonus II Gonatas destroyed a Gallic army near Lysimachia in Thrace, a victory that helped him win the Macedonian throne. Other Gauls founded a kingdom in Thrace with its centre at Tylis, which lasted until about 212 BC.

Several groups crossed into Asia Minor in 278/277 BC at the invitation of King Nicomedes I of Bithynia, who hired them as allies. They became the Galatians, who settled in central Anatolia and raided the region for generations.

Sources and key people

Almost everything known about the invasion comes from Greek and Roman writers working long after the events. The fullest account is by Pausanias, who wrote his guide to Greece in the 2nd century AD. Justin’s summary of the lost history of Pompeius Trogus adds details, and earlier inscriptions from Delphi confirm the attack and the thanksgiving that followed. Because the Gauls left no written records, the story is told entirely from the point of view of their enemies.

Brennus himself is known only through these sources, which portray him as bold and contemptuous of the Greek gods. Callippus of Athens led the Greek resistance at Thermopylae. Antigonus II Gonatas, a grandson of Antigonus I, turned his later victory over the Gauls into a claim to the Macedonian throne, which his descendants held until the Roman conquest.

Myths and facts

A Roman story claimed that treasure looted from Delphi ended up in Tolosa (Toulouse) in Gaul, where the Roman consul Caepio seized it in 106 BC. The ancient geographer Strabo already doubted this, noting that the Greek sources say the Gauls were repulsed before plundering the sanctuary.

The invasion is also often confused with the Gallic sack of Rome around 390 BC. That event, described in the Gallic sack of Rome, was led by a different Brennus a century earlier.

Timeline

• 281 BC: Ptolemy Keraunos kills Seleucus I and takes the throne of Macedonia.
• 280/279 BC: Gauls under Bolgius defeat and kill Ptolemy Keraunos.
• 279 BC: Brennus leads a great army into Greece and is held at Thermopylae.
• 279 BC: A Gallic force sacks Callium in Aetolia; the Gauls outflank Thermopylae.
• Winter 279/278 BC: The attack on Delphi is repulsed; Brennus dies.
• 278/277 BC: Gallic groups cross into Asia Minor.
• 277 BC: Antigonus Gonatas defeats the Gauls at Lysimachia.

Why it matters

The invasion was the deepest Celtic penetration into the Greek world. The defence of Delphi was celebrated for centuries, notably in the Soteria festival held at the sanctuary, and the Gauls became a stock image of the barbarian enemy in Hellenistic art and politics.