Cleisthenes Introduces Law of Ostracism

Athens had just slipped the grip of Hippias when Cleisthenes, the city’s reformer, faced a familiar Greek problem: how to keep one name from growing so large it swallowed the polis. He had already redrawn the demes, rebalanced tribes, and shifted decision-making to the Assembly on the Pnyx. But he knew memory lingered—fear of another tyrant standing on the Acropolis, fear of factions brawling in the Agora [1][15].

So he added an odd device to the constitution, described later by Aristotle as the law of ostracism. Once a year, citizens could decide whether they wished to hold an ostrakismos. If they did, a second gathering would follow: each man scratching a single name on a shard, and the city speaking in terracotta [1][2][15]. The instrument punished no crime. It left estates untouched. It simply removed a person who had begun to loom too large, for ten years [2].

The places where this would happen were familiar and public. On the Pnyx, the preliminary vote—amid the clack of staffs and the murmurs that rose and fell like the sea off Piraeus. In the Agora, inside a fenced precinct, the ostraka piled up—red-brown clay cut with charcoal lines and neat letters [2][15]. The Kerameikos, the cemetery by the city gate, would someday hold thousands of those shards, a material memory of fear mixed with prudence [11].

It was a ritual, not a trial. Plutarch emphasized that the ban was mild: ten years’ absence, ten days to depart Attica, all without stigma in law [2]. That mildness mattered. Exile had long been a weapon in elite feuds; Athens converted it into a civic ordinance and absorbed its violence into a vote [9]. The rule aimed to prevent, not to punish. To drain pressure before it burst.

The law did not bite at once. Aristotle reports it slept until two years after Marathon, when Athenians, freshly victorious and suddenly powerful, decided to use it [1]. That delay tells us something about purpose. Ostracism existed for the moments when glory and danger overlapped, when dazzling leaders and surging factions tugged the city’s fabric. In those moments, the law offered a ten-year pause.

When Cleisthenes set this mechanism into the constitution, he gave his city a trapdoor, not a scaffold. Its hinge was a quorum: if fewer than 6,000 ballots fell into the baskets, no one left [2]. If the votes crossed that line, the top name had to go. No speeches in court. No prosecutors. Just the scrape of styluses across clay and the proclamation over the Agora’s hum.

Athens would learn to use it against names we still know—Aristides, Themistocles, Cimon—and against names the shards alone preserve. But in 508/7, the achievement was institutional, not personal. A law that domesticated exile, glinting like bronze in the winter sun over the Stoa of Attalos, and promising the demos a way to sideline even its darlings before admiration turned into rule [2][9][15].