Sparta was a military city state with a monarchy as the form of government. Spartan society revolved around discipline and honor. The main focus of the Spartan government is the military. They were famous for there status as a major military power in the time period. The soldiers were the equivalent of modern day special forces. They were trained from the age of seven to the age of 20 in the arts of warfare. At the age of 30, the Spartans were allowed to leave the barracks to start a life, however, they were still bound to the military. At the age of 60, the Spartans could retire from military service.
In 725 B.C. the Spartans began the conquest of Messenia. Messenia occupied very fertile land and at the time the Spartans needed to feed their enlarging population. While they were successful in taking the city, the Argos aided the enslaved Messenians in revolting against their occupiers. Even with the help the Messenians remained enslaved. Still the uprising nearly razed Sparta itself. Because of this the Spartans switched to the militaristic government they're so famous for.
The Spartans next conquest was towards neighboring Tagea. This was extremely well played on the part of the Spartans as instead of conquering Tagea, they signed a treaty. This treaty declared that the Tageans were to grant the Spartans soldiers and supplies whenever they needed them. This would prove to be very useful in future engagements.