Cleomenean War - Battle of Sellasia

Battle of Sellasia

The destruction of Megalopolis shook the Achaean League. Cleomenes set off with his army to raid the territory of Argos, knowing that Antigonus would not resist him due to a lack of men. Cleomenes also hoped that his raid would cause the Argives to lose confidence in Antigonus because of his failure to protect their territory. Walbank describes this raid as being "an impressive demonstration, but it had no effect other than to make it even more clear that Cleomenes had to be defeated in a pitched battle."

In the summer of 222 BC, Antigonus summoned his troops from Macedon, who arrived together with other allied forces. According to Polybius, the Macedonian army consisted of 10,000 Macedonian infantry, most of them armed as phalangites, 3,000 peltasts, 1,200 cavalry, 3,000 mercenaries, 8,600 Greek allies, and 3,000 Achaean infantry, making a total of 29,200 men.

Cleomenes had fortified all the passes into Laconia with barricades and trenches before setting off with his army of 20,000 men to the pass at Sellasia, on the northern border of Laconia. Overlooking the pass at Sellasia were two hills, Evas and Olympus. Cleomenes positioned his brother, Eucleidas, with the allied troops and the Perioeci on Evas; he stationed himself on Olympus with 6,000 Spartan hoplites and 5,000 mercenaries.

When Antigonus reached Sellasia with his army, he found it well guarded and decided against storming the strong position. Instead he pitched camp near Sellasia and waited for several days. During this time, he sent scouts to reconnoiter the areas and feign attacks on Cleomenes' position.

Unable to force a move from Cleomenes, Antigonus decided to risk a pitched battle. He positioned some of his Macedonian infantry and Illyrians facing the Evas hill in an articulated phalanx. The Epirots, the Acarnanians and 2,000 Achaean infantry stood behind them as reinforcements. The cavalry took a position opposite Cleomenes' cavalry, with 1,000 Achaean and Megalopolitan infantry in reserve. Together with the rest of his Macedonian infantry and mercenaries Antigonus took his position opposite that of Cleomenes.

The battle started when the Illyrian troops on the Macedonian right wing attacked the Spartan force on Evas. The Spartan light infantry and cavalry, noticing that the Achaean infantry was not protected at the rear, launched an assault on the back of the Macedonian right wing, and threatened to rout it. However, at the critical moment, Philopoemon of Megalopolis (who later became one of the greatest heroes of the Achaean League, eventually conquering Sparta), tried to point out the danger to the senior cavalry commanders. When they did not take notice of him, Philopoemon gathered a few other cavalrymen and charged the Spartan cavalry. The Spartans attacking from the rear broke off their engagement with the enemy, which encouraged the Macedonians to charge at the Spartan positions. The Spartans' left flank was eventually forced back and thrown from their position and their commander, Eucleidas, killed; they fled the field.

Meanwhile, the Macedonian phalanx on the left flank engaged the Spartan phalanx and mercenaries. During the initial assault, the Macedonian phalanx gave a considerable amount of ground before its weight drove back the Spartan phalanx. The Spartans, overwhelmed by the deeper ranks of Macedonian phalanx, were routed, but Cleomenes managed to escape with a small group of men. The battle was very costly for the Spartans; most of their army was routed with only 200 of the 6,000 Spartans that fought surviving the battle.