Spartan society is one of the most debated in ancient history, partly because the sources are problematic — most of our information comes from outsiders, often admiring ones — and partly because the system was so deliberately different from the Athenian norms that dominate the sources.

The defining institution was the agoge, the state-run system of education and training that all male Spartiate citizens underwent from age 7. Boys were separated from their families, organized into age cohorts, subjected to physical hardship, trained in combat, and taught to identify their primary loyalty with the Spartan state rather than their families. The system aimed to produce physically formidable, obedient soldiers who saw military service as the purpose of their lives.

Spartan women occupied a position markedly different from women elsewhere in the Greek world. They received physical training, managed their households and estates while men were in the barracks, could own property, and were expected to be as physically vigorous as the men. The famous Spartan mother who told her son to return 'with his shield or on it' encapsulates an ideology that valued military virtue over maternal attachment — an ideology that may have been partly constructed after the fact but reflects genuine Spartan self-presentation.

The helot system — enslaved peoples of Laconia and Messenia who worked Spartan land while Spartiates trained and fought — is the dark foundation of Spartan military culture. The annual ritual declaration of war against the helots, which licensed the killing of any helot who seemed dangerous, and the krypteia (a secret police institution targeting helot leaders) reveal a society permanently organized around the suppression of a subject population that outnumbered the Spartiates by perhaps 7 to 1.