Spartan military organization was the structure of the army which was subject to periodic reorganizations.
The army was organized and fought in three tribes during the Second Messenian War which were the “Pamphyloi, Hylleis and Dymanes”. It was the normal form of politico military organization was the warrior band. Another subdivision of the tribe was “fraternity” was formed to introduce more formal politico military organization into aristocratic society. In 594, Solon introduced the tribal system to Athens and the four tribes divided. If it was based on Spartan model, the total warrior population would have been 4,500 men. As the Greek population grew, the Greeks tended to introduce new political and military structures in the archaic period. The reform was connected with the start of Sparta’s war with Tegea and a political upheaval during the ephorate of Chilon.
The Ephorate was the biggest constitutional change which occured after the first Messenian war. The Ephorate was five men.
After the Spartan population had fallen, the manpower shortage late became so serve that a new organizational structure was developed. The army divided into six; each group had 576 men and 100 cavalry were attached to it.