The earthquake of 466 or 464 B.C. was one of the most significant events in Spartan history. Why two dates? Because we have two historical accounts which locate the event in time that do not agree exactly.
The first source is Thucydides (The Peloponnesean War, Book 1) writing of the Thasian revolt:
“The Thasians, defeated in battle and under siege, appealed to the Lacedaemonians and asked them to rescue them by invading Attica. They promised to invade, keeping this from the Athenians, and intended to but were prevented by the occurrence of an earthquake, at which time the Helots, also the Thouriatai and Aithaians among the Perioikoi, revolted and fled to Ithome.”
Without Spartan aid, the Thasians surrendered.
Then in Book 4:
“Twenty-nine years later, the Athenians came again when Hagnon son of Nikias was sent out as founder, and they drove out the Edonians and settled the site which was formerly called Ennea Hodoi.”
The new city was known as Amphipolis and was known to have been founded in 437/436 B.C. If you add twenty nine years to 437/436 you arrive at 465/464 B.C. as the year of the earthquake.
Our other source is Plutarch (Cimon);
“In the fourth year of the reign of Archidamus, the son of Zeuxidamus, King of Sparta, there happened in the country of the Lacedaemon the greatest earthquake that was known in the memory of man; the earth opened in chasms, and the Mountain Taygetos was so shaken, that some of the rocky points of it fell down, and except five houses, all the town of Sparta was shattered to pieces.”
According to Diodorus, Archidamus reigned for forty-two years, and we know his son Agis was on the throne in 426 B.C. We also know that his father was alive in 428 B.C. If he died in 427 and you add forty-two and subtract three (Greek method of inclusive counting), you arrive at 466 B.C. for the earthquake.
We have the descriptions of the event from Plutarch and Diodorus but little else to say about what really happened that day. Before we speculate on lives lost (we’ll be guessing), let’s use the behavior of Sparta’s enemies as a guide to how devastating the event must have been.
Messenia revolted immediately. The Periokoi towns of Thouriatai and Aithaians revolted immediately. Athens began a serious of provocative acts, signing a treaty with Sparta’s arch enemy Argos in 461 B.C. In 459, Athens came to the aid of Egyptian insurgents fighting the Persians, and in 457 B.C. she attacked the Spartan allies Algina, Epidauros, and Corinth. This Athenian boldness would not have been possible unless she perceived that Sparta was impotent.
Sparta succeeded in ending the Messenian revolt, but it took over five years to do so. She also battled Athens twice: inconclusively in 457 B.C, and more decisively in 446 B.C. when the Athenians where forced to rein in their designs on central Greece. But Sparta remained weak as we shall see from the casualty estimates.
Plutarch describes the catastrophe as follows:
“They say that a little before any motion was perceived, as young men and the boys grown up were exercising themselves together in the middle of a portico, a hare, of a sudden, started out just by them, which the young men, though all naked and daubed with oil, ran after for sport. No sooner were they gone from the place, than the gymnasium fell down upon the boys who stayed behind, and killed them all.”
If we start with the assumption that they were 9,000 Homoioi in the Spartan army and assume this to be one fourth of the population, when we add 4,000 more for Helot laborers, we arrive at 40,000 people in Sparta that day. According to Diodorus “houses collapsed from their foundations and more than twenty thousand Lacedaemonians perished.” If close to being accurate this number suggests that half the people in Sparta were killed by the earthquake.
The heaviest losses may have been mothers and small children who would normally be in their homes. Loss of mothers caused a chain reaction through the loss of at least two generations of births, because new daughters born after the disaster would have to grow up and raise their offspring. As far as male children goes, young sons could be replaced more quickly than those in the midst of their training, who left a hole in the army.
Two generations later was 430(?), a point where the human losses had been replaced and a steady growth in Homoioi could continue. Perhaps this is why the Spartans were now ready to fight the Athenians for control of Greece.