The battle of Haliartus (395 BC) was the first significant fighting during the Corinthian War (395-386 BC) and was a Spartan defeat that saw the death of Lysander, their victorious leader from of the Great Peloponnesian War.
At the end of the Great Peloponnesian War Sparta had alienated her allies in Corinth and Thebes by refusing to allow them to share the spoils of victory. They continued to anger the Thebans by establishing a presence in Thessaly, an area that Thebes fell within her sphere of influence. In 401-400 they sided with the Persian rebel Cyrus the Younger, but he was defeated at Cunaxa (400 BC). This left the Greek cities of Asia Minor exposed to Persian attack. The Spartans decided to support them, triggering the Persian-Spartan War of 400-387 BC. Thebes and Corinth refused to contribute troops for this campaign, which was led by the Spartan king Agesilaus II. At the same time the Persians sent envoys to Greeks to try and stir up opposition to Sparta at home.
The almost inevitable war was triggered by an incident in central Greece. The Thebans, who wanted a war, needed to find a way to force the rest of Boeotia to join in. According to our sources they did this by stirring up trouble between two of their western neighbours - Phocis and Locris. The Thebans convinced the Locrians to levy a tax in a disputed border area. The Phocians responded with an invasion of Western Locris. The Locrians were allied with Boeotia, and called for assistance. The Boeotians responded by planning an invasion of Phocis. In turn the Phocians asked for help from Sparta. The Spartans demanded that the Boeotians cancelled their plans. When the Boeotians refused to comply and raided into Phocis, the Spartans decided to go to war.
The Spartans decided to conduct a two pronged invasion of Boeotia. The main army was to concentrate at Tegea, under the command of King Pausanias, and then advance through Corinthian territory and invade Boeotian from the east. Lysander, the key Spartan commander late in the Peloponnesian War, was sent to Phocis to raise a local army and then attack Boeotia from the west. The two forces were to meet at Haliertus, then on the southern shores of Lake Copais.
Lysander gathered a reasonably powerful army. He probably had a few hundred Spartans, but the core of his army was made up of around 2,000 Phocians and forces from Sparta's northern allies around Ainis, Malis and Mount Oeta (areas just south of ancient Thessaly).
After gathering his army Lysander advanced into north-western Boeotia. His first success came at Orchomenus, on the north-western shores of Lake Copais, where he was able to convince the locals to switch sides. He then advanced down the western shores of the lake, where his troops captured Lebadeia. He probably bypassed Coronea, on the south-western shore of the lake, and advanced towards Haliartus.
As Lysander advanced, the Boeotians searched for allies. They found them in Athens, still slowly recovering from her crushing defeat in 404 BC and the civil strife that followed. Even so the Athenians were willing to enter into an alliance with Boeotia. As the Spartans were already actively campaign in Boeotia this new alliance was immediately activated and the Athenians sent an army into Boeotia, commanded by Thrasybulus. This Athenian army quickly reached Thebes, and took over the defence of the city. This allowed the main Theban army to move west to face Lysander.
Xenophon, writing not long after the battle, gives a brief description of events. Lysander arrived outside Haliartus a few days before Pausanias with the main Spartan army. Instead of waiting for Pausanias, Lysander decided to try and take the town. He approached the walls and attempted to convince the inhabitants to change sides, but the Thebans already had some troops inside the walls and this failed. Lysander then attempted to attack the city. News of his activities reached the main Theban army, which rushed to the scene. Xenophon wasn't sure if Lysander had been ambushed, or if he had deliberately chosen to fight outside the walls. Whichever was the case, the Thebans attacks and Lysander was killed. A trophy to celebrate the victory was built just outside the gates.
In the aftermath of this defeat the rest of Lysander's men fled south towards the mountains. The Thebans followed in hot pursuit, but suffered at least two hundred dead in fighting in the mountains and were forced to retreat.
Plutarch's Life of Lysander provides a similar picture, although with some more details and a few differences. In his account the Thebans discovered that the Spartans planned to unite at Haliartus after capturing a messenger moving between their two forces. The main Theban army arrived at Haliartus before Lysander. They posted part of their army inside the walls and the rest somewhere nearby. At first Lysander decided to camp on a nearby hill and wait for Pausanias to arrive, but later in the day he became impatient and advanced in a column towards the walls. The Theban troops left outside the city advanced anti-clockwise around the walls and approached Lysander's men from the rear, near a spring called Cissusa.
The troops inside the walls waited until Lysander and his soothsayer were isolated in front of their army and then attacked. Lysander was killed in this initial attack (by Neochorus of Haliartus), and the Spartan advance guard fled back towards the main force. The Thebans kept coming, and the Spartan army fled into the mountains. Plutarch also reports the Theban setback in the mountains, which he blamed on the desire of some Thebans to clear their names after they were suspected of being pro-Sparta. According to Plutarch the Spartans lost 1,000 dead and the Thebans 300.
Both sources agree on what happened next. By the time Pausanias arrived with the main Spartan army the Athenians had arrived from Thebes. He briefly considered fighting a second battle, but decided that it wasn't worth the risk. One major factor was that Lysander's body was close to the city walls, and would thus have been difficult to rescue. Pausanias asked for a truce to recover the bodies, acknowledging the Spartan defeat. He then led his army west into Phocis, where Lysander was buried.
News of this defeat caused outrage in Sparta. Pausanias was put on trial, accused of not moving fast enough to reach Haliartus, failing to fight to try and recover Lysander's body, and for his actions at the Piraeus a few years earlier, where he had allowed the Athenians to restore their democracy. Pausanias wisely decided not to attend the trial and instead fled to Tegea, spending the rest of his life in exile. He was succeeded by his underage son Agesipolis. As a result the Spartans had lost two experienced leaders in a short time and were forced to recall Agesilaus II from his campaign against the Persians.