Year 279 BC was a year in the Roman calendar used before the Julian calendar was created. During that time, it was called the Year of the Consulship of Publius Sulpicius Saverrio and Publius Decius Mus. It was also sometimes referred to as year 475 Ab urbe condita, which means "from the founding of the city." The label "279 BC" for this year was first used during the early medieval period, when the Anno Domini calendar system became the common way to record years in Europe.

Events

Gauls, led by Brennus, attack Greece. Part of the army, commanded by Bolgios, defeats a Macedonian army led by Ptolemy Keraunos, who dies in the battle. At Thermopylae, a narrow pass on the east coast of Central Greece, Brennus' forces face heavy losses while fighting the Greek defenders, the Phocians and Aetolians. Eventually, Brennus finds a way around the pass, but the Greeks escape by sea. Brennus advances to Delphi, where he is defeated and forced to retreat. He later dies from wounds received in the battle. His army retreats to the Spercheios River, where it is defeated by the Thessalians and Malians. Some survivors settle in a region of Asia Minor that becomes known as Galatia, while others settle in Thrace and establish a short-lived city called Tylis.

After Ptolemy Keraunos dies, Antipater II regains the throne of Macedonia. However, his rule lasts only a few months before he is killed by his cousin, Sosthenes, who becomes the new king of Macedonia.

The Phocians are allowed back into the Amphictyonic League after helping defend Delphi against the Gauls.

The Carthaginians and Romans agree to support each other against a shared enemy. The Carthaginians provide Rome with money and ships to help fight Pyrrhus, king of Epirus.

Pyrrhus realizes he cannot capture Rome and offers peace terms to the Romans. He sends his advisor, Cineas, to negotiate. Cineas demands that Rome stop attacking Greek cities in southern Italy and return lands taken from the Bruttii, Apulians, and Samnites. The Romans refuse these demands, largely because of the influence of Appius Claudius Caecus, a former Roman leader.

In renewed fighting, Pyrrhus leads a combined force of Tarantine, Oscan, Samnite, and Greek soldiers against the Romans, led by consul Publius Decius Mus. At the Battle of Asculum, Pyrrhus wins a battle known as a "Pyrrhic victory" because his forces suffer heavy losses. Pyrrhus is reported to have said, "One more victory against the Romans and we shall be utterly ruined!" Disheartened, Pyrrhus retreats to Tarentum and sends Cineas to negotiate peace with Rome again. These talks do not result in an agreement.

Ptolemy II of Egypt continues to cause conflict with Antiochus by capturing the city of Miletus in southwestern Asia Minor from him.

The Scordisci Celts establish a city called Singidon, later known as Singidunum, which is now the Serbian city of Belgrade.

General Bai Qi of the State of Qin attacks the State of Chu and captures the cities of Yan and Deng. General Lian Po of the State of Zhou defeats an army from the State of Qi.

Deaths

• Brennus, a leader of the Gauls' army, led an invasion of Macedonia and northern Greece in 279 BC
• Ptolemy Keraunos, a king who ruled Macedonia, reigned from 281 to 279 BC