The battle of Sphacteria (425 BC) was the second part of a two-part battle which ended with the surrender of a force of Spartan hoplites (Great Peloponnesian War). The chain of events that led to this almost unprecedented disaster began when an Athenian force under the command of Demosthenes landed on the rocky headland of Pylos, in the south-west of the Peloponnese and fortified their position. The Peloponnesian army under King Agis abandoned their short invasion of Attica and returned to the Peloponnese, while the forces already at Sparta moved west to deal with the new threat.
For a brief period Demosthenes was in serious trouble. The Spartans summoned their fleet to Pylos, and he found himself besieged by land and sea. The Athenian position was on a headland at one end of the Bay of Pylos. The island of Sphacteria ran across the mouth of the bay, and was occupied by the Spartans. The Spartan fleet moved into the bay, trapping the Athenians and prevented any supplies from reaching them. In the resulting battle of Pylos the Athenians managed to hold off a two-pronged Spartan assault, but they were really saved by the arrival of an Athenian fleet. This fleet inflicted a heavy defeat on the Spartan fleet inside the bay, in the process lifting the blockade of Pylos.
The tables were now turned on the Spartans. A force of 420 Spartan hoplites, under the command of Epitades son of Molobrus was trapped on Sphacteria. The Spartans responded by sending senior members of their government to Pylos to examine situation. When it became clear that they couldn't hope to get supplies onto the island or rescue the hoplites they asked the Athenians for an armistice. The biggest weakness in the Spartan system was the shortage of full citizens, and they could hardly afford to lose 420 full Spartans. This was reflected in the terms they agreed with the Athenians. Every warship that had taken part in the earlier fighting and every warship in Laconia was to be handed over to the Athenians for the duration of the armistice. The Spartans were to stop all attacks on Pylos, while the Athenians stopped attacking Sphacteria, and allowed a fixed amount of food onto the island. The armistice would stay in place while Spartan representatives went to Athens to offer peace terms.
The peace negotiations and their aftermath do not reflect well on the Athenians. They demanded the return of lands lost at the end of the First Peloponnesian War, and when the negotiations broke down refused to honour the terms of the armistice and kept the Spartan warships. The armistice lasted twenty days.
After the failure of the negotiations the fighting resumed. The Spartans continued their attacks on the Athenians on Pylos, while the Athenians maintained the naval blockade of Sphacteria. Both sides were effectively under siege, but at first it was the Spartans who put the most effort into getting supplies to their troops. Volunteers were asked to try and get supplies onto the island, with a cash reward for free men and freedom as the reward for helots. Any boats used in the operation were valued beforehand, so it didn’t matter if they were lost. Some men waited for the right weather and effectively rammed the island at full speed, damaging their boats but winning the reward. Others swam in under water, towing supplies protected by skins.
As the siege dragged on the Athenian people became concerned that the Spartans would escape. The politician Cleon, who had played a major role in convincing the people to reject the Spartan peace offer, became increasingly unpopular. In an attempt to restore his popularity he tried to blame the general, Nicias son of Niceratus, for the failures, claiming that a true leader would have easily captured the island by now. This badly backfired, for the Athenian people began to ask why Cleon wasn't leading the army if it was that simple. Nicias added to his problems by giving him permission to take any troops that he required and take command of the siege. Eventually Cleon was backed into a corner, and had no choice other than to go to Sphacteria. He now raised the stakes once again by announcing that he would take the island in twenty days, without using any fresh Athenian troops.
Cleon timed his arrival at Sphacteria perfectly. Demosthenes had been unwilling to risk a landing on the island because it was covered in thick woodland, with no paths, and he believed that this would give the Spartans too big an advantage. Just before Cleon arrived one of the Spartans accidently set the woods on fire, and most of the trees burnt down. The fire also revealed a number of landing points, and that there were more Spartans on the island than previously believed, making them an ever bigger prize.
The two Athenian generals began by sending a herald to the island to ask the Spartans to surrender on generous terms. When this offer was rejected, they waited for a day and then launched a surprise attack on the island. The Spartans were divided into three camps. The main camp, under their commander Epitades, was in the centre of the island. This was both the most level and best provided with water. A guard of thirty hoplites was at the end of the island the Athenians chose to attack (probably the southern end), and another small detachment was posted at the opposite end, facing the headland of Pylos. This was the rockiest end of the island, and was topped with an old fort that the Spartans hoped to use as a final refuge. This attack came on the seventy-second day after the naval battle that had trapped the Spartans.
The Athenians caught the Spartans out by loading their 800 hoplites onto the ships while it was still dark. The ships then put out to sea as if they were about to mount their normal daily patrols, but instead landed on the island. The first Spartan post was overwhelmed. This allowed Demosthenes to bring over the rest of his army - 800 archers, at least 800 peltasts, the Allied contingents and the crews of the seventy Athenian warships. This army was then divided into groups of around 200, and these groups were posted on high ground all around the main Spartan position. The Greeks are often accused of being unimaginative in warfare, relying entirely on simple clashes between hoplites, but here we see Demosthenes using a different tactic. The Spartans would find themselves in a trap. If they attempted to attack any part of the Athenian line they would be exposed to attack from the rear, while the lightly armed Athenian troops would be able to retreat from the heavily armoured Spartan hoplites.
When Epitades realised that the Athenians had landed on the island he formed up his men and moved to attack the Athenian hoplites, expected the standard clash between two lines of similar troops. Instead the Spartans found themselves being harried from both flanks by the bowmen, peltasts and stone throwers. The Athenian hoplites refused to come forward and fight, so the Spartans were denied their main target. They were sometimes able to close up with the light troops, but not to crush them. Eventually they were forced to retreat back up the island to the fort. The Athenians followed, and launched a series of frontal assaults on the fort, but this time the advantages were with the Spartans, and these attacks failed to push the Spartans out of their final defensive lines before the fort itself.
The stalemate was broken by the commander of the Messinian contingent. He asked Cleon and Demosthenes to give him some archers and light troops. He then picked his way around the rocky coastline of the island, until he was in position on some high ground behind the fort. When these troops appeared behind them the Spartans abandoned their outer lines and pulled back.
At this point Cleon and Demosthenes called a halt to the fighting, and once again sent a herald to offer surrender terms. By now the Spartans had lost Epitades, who had been killed, while their second in command, Hippagretas was badly wounded and believed falsely to be dead. This left the third in command, Styphon son of Pharax, in charge. According to Thucydides most of the Spartans lowered their shields and made it clear that they wanted to surrender when they first heard the heralds, so Styphon had no choice other than to enter into surrender negotiations. After consulting with the Spartans on the mainland, who have him no useful advice ('make your own decision about yourselves, so long as you do nothing dishonourable'), Styphon decided to surrender.
The Athenians had captured a very valuable prize. Of the 440 hoplites who had been trapped on the island, 292 were captured and taken to Athens. Of these 120 were full Spartans, a sizable proportion of a very small group. The surrender of the Spartans caused shockwaves across the Greek world. Spartans were not expected to surrender, but to fight to the death, regardless of the odds against them. The surrender also caused great despondency in Sparta, and triggered a series of peace offers. The prisoners were still a major factor four years later, when the Peace of Nicias (421 BC) did actually end the war for a short period. One of the clauses of the peace treaty saw the Athenians return all Spartans in prison in Athens or in any Athenian dominion.