The fall of Potidaea in 430/429 BC was supposed to settle Chalcidice. Athens had spent three years and 420 talents a year strangling that city into surrender, and the price had broken Pericles' political standing and helped seed the plague that killed him. But the Chalcidian peninsula did not pacify. The Chalcidian League - a loose federation of small Greek towns scattered across the three fingers of land that reach down into the Aegean from Macedonia - kept resisting. To collect tribute and make examples, Athens dispatched Xenophon, son of Euripides (not the more famous Xenophon, who was still a boy), with two thousand hoplites, two hundred cavalry, and around five hundred light troops. Their target was Spartolos.

Xenophon's army began the campaign in the standard manner - destroying the wheat and barley in the fields outside the town to starve the population into surrender. While his soldiers worked, his diplomats opened negotiations with pro-Athenian factions inside Spartolos. The talks went poorly. The anti-Athenian faction sent urgent messengers to Olynthus, the largest city of the Chalcidian League, asking for help. An army from Olynthus, Spartolos, and several other Chalcidian towns answered the call and met the Athenians in the open.

When the Chalcidian phalanx clashed with the Athenian, the result was what hoplite warfare was supposed to deliver: a clear, decisive answer in twenty minutes of brutal pushing. The Chalcidian center and right - local hoplites - gave way first. The hired Peloponnesian mercenaries on the left had to fall back to avoid being flanked. The Chalcidians retreated into Spartolos. From inside the walls, watching this happen, was an officer who had thought hard about what hoplites could not do. He saw what had happened to the Chalcidian phalanx and decided not to repeat it. While the Athenians regrouped on the field, he sent for help.

The reinforcements from Olynthus brought what the Chalcidians had been missing - more cavalry and more peltasts. Peltasts were light infantry from Thrace and the surrounding regions, named for the wicker pelta shields they carried. Their weapon was the javelin, and their tactic was to throw, run, and throw again. They could not fight a hoplite shield-to-shield. They did not need to. When the Chalcidian forces came out a second time, they refused close combat. Cavalry circled the Athenian flanks. Peltasts threw javelins from a distance hoplite spears could not reach, then sprinted back when the heavy infantry charged. Each Athenian counter-attack ended with the light troops vanishing and the javelins continuing to come. Athenian formation began to fray. The back ranks broke first, abandoning the front. Then surrounded men were killed where they stood. General Xenophon died on the field. So did his fellow generals. Four hundred and thirty Athenian dead in addition to the commanders - between a fifth and a fourth of the force that had marched out that morning.

Spartolos was, by Peloponnesian War standards, a small disaster. Greater catastrophes lay ahead - the Sicilian Expedition, the slaughter at Aegospotami, eventual Athenian surrender in 404 BC. But this fight in Chalcidice taught Athens lessons it kept relearning at higher cost. Light troops and cavalry, used well, could undo a hoplite force on broken ground. The phalanx was a tool, not an answer. A generation later Iphicrates and Chabrias would refine peltast tactics into something Athenian commanders could use offensively, and Philip and Alexander of Macedon would build whole armies around the marriage of phalanx, cavalry, and skirmishers. The site of Spartolos has not been securely identified - it lay somewhere in central Chalcidice, the inland farm country between the gulf cities. Olive groves, vineyards, low hills. A pretty piece of country to die in.