Pyrrhus' invasion of the Peloponnese

Pyrrhus' invasion of the Peloponnese in 272 BC was an invasion of south Greece by Pyrrhus, King of Epirus. He was opposed by Macedon and a coalition of Greek city-states (poleis), most notably Sparta. The war ended in a joint victory by Macedonia and Sparta.

Pyrrhus' invasion of the Peloponnese

The Siege of Sparta by Pyrrhus,
by François Topino-Lebrun
Date272 BC
Location
Result Macedonian and Spartan victory
Territorial
changes
Epirus loses control of Macedon and Thessaly
Belligerents
Epirus,
Macedonia (Aeacid)
Argive democratic faction
Macedonia (Antigonid),
Sparta,
Messene,
Argive oligarchic faction
Commanders and leaders
Pyrrhus of Epirus ,
Ptolemy 
Antigonus II Gonatas,
Areus I,
Acrotatus
Strength
27,000 troops
25,000 infantry,
2,000 cavalry,
24 war elephants
Unknown

After being defeated by the Roman Republic in the Pyrrhic War in 275 BC, Pyrrhus (r. 297–272 BC) decided to turn his attention to Greece. He declared war on Antigonus Gonatas (r. 283–239 BC) of Macedon and in a rapid campaign, managed to defeat him and make himself king of Macedon. In 272 BC, Pyrrhus agreed to assist the disgruntled Spartan prince, Cleonymus, who requested his assistance in securing the Spartan throne.

Pyrrhus advanced with his army through central Greece and upon reaching the Peloponnese, he marched against Sparta. The city was sparsely defended at the time as the majority of its army had been taken to Crete by King Areus I (r. 309–265 BC). The Spartans led by Crown Prince Acrotatus were able to withstand a series of Epiriote assaults until Macedonian reinforcements and Areus' army arrived to relieve the defenders.

Following the arrival of the relieving force, Pyrrhus lifted the siege and prepared to winter in Laconia. However, he was approached by an Argive citizen who requested his assistance in overthrowing the government of Argos. Seeking to take advantage of the opportunity, Pyrrhus took his army to Argos, being harried along the way by the Spartans. Whilst attempting to seize Argos by night, Pyrrhus was set upon by his Argive opponents as well as the Spartans and Antigonus' Macedonians. In the ensuing mêlée, Pyrrhus was slain. His death prompted the capitulation of his army and the reestablishment of a Macedonian hegemony over Greece.