There is something very intriguing in the fact that Sparta’s most consequential king has largely been forgotten. While Leonidas and his three hundred men have been immortalized by Hollywood and popular imagination, Cleomenes I, the man who arguably did more than anyone to make Sparta the dominant force in Greece, gets a fraction of the attention, and that is a shame because his story is one of the most gripping and darkest in all of Ancient Greek history.
Who was Cleomenes I, Sparta’s ferocious King?
Cleomenes came to the throne of the Agiad dynasty not as a conqueror inheriting an empire but as a ruler stepping into a brutally competitive world. This was a world where the Greek city-states were in constant competition for power and quite literally for their citizens’ lives. Herodotus, our main source for his life, was not exactly a fan of Cleomenes. The great historian hints more than once that the king was mentally unstable and even mad. However, historians today tend to interpret that differently. What Herodotus called madness looks, on closer inspection, like a kind of political ruthlessness that his more conservative Spartan contemporaries simply had no framework to understand.
One of the strangest footnotes of his reign is that Cleomenes may have accidentally invented Athenian democracy. When he marched into Athens to remove the tyrant Hippias and extend Spartan influence, he created a power vacuum he never intended. Into that vacuum stepped Cleisthenes, who used the moment to lay the groundwork for a democratic system that would eventually grow into Sparta’s greatest rival. History is full of these ironies, but few are quite as consequential as this one.
The Battle of Sepeia
His defining military moment came at the Battle of Sepeia against Argos. After routing the army of Argos, he cornered the survivors in a sacred grove where they had taken refuge, expecting the sanctuary to protect them. Cleomenes ordered the grove burned. The men inside died in the flames.
It was a war crime by any standard, ancient or modern, and it shocked Greece at the time, but it also worked. Argos was effectively neutralized for a generation, and Spartan dominance over the Peloponnese was no longer in question.
Cleomenes’ downfall
His downfall, when it came, was spectacular in its self-destruction. To get rid of his co-king and political rival Demaratus, Cleomenes bribed the priests at Delphi. He essentially corrupted the oracle itself, which was the most sacred institution in the Greek world, and he did so to declare Demaratus illegitimate. When the scheme was uncovered, his position became untenable. He fled into exile, returned under a cloud of suspicion, was imprisoned by his own family, and reportedly died in custody, having apparently inflicted terrible wounds on himself. Historians have noted how his end exposed the inherent contradictions and paranoia running through Sparta’s unusual dual kingship system.
What Cleomenes understood, and what his peers never forgave him for, was that Sparta could not survive by staying still and accepting its inevitable decline. His instinct was always to project power outward and to intervene and act before others could act against Sparta. That made him exceptionally effective. It also made him dangerous, and ultimately, he acquired enemies in the one place where he could not afford to have them—inside his home city of Sparta itself.
He was not a good man by conventional measures. After all, he burned refugees alive in a holy grove and corrupted the Delphic oracle without hesitation. However, his reign cannot be reduced to a simple moral lesson. Cleomenes I remains one of the ancient world’s most unsettling figures. He was a leader whose greatest qualities and worst instincts were, in the end, exactly the same thing.
Related: One Man’s Plot Unintentionally Launched Democracy in Ancient Athens
