The Greek invaders who entered southern Greece, or the
Peloponnesus,  were known as Dorians. They founded the city of Sparta, in
the district of Laconia. By the close of the sixth century B.C. the Spartans
were able to conquer their immediate neighbors and to organize some of the
city-states of the Peloponnesus into a strong confederacy called the
Peloponnesian League. The members of the league did not pay tribute, but they
furnished troops to serve in war under Spartan leaders, and they looked to
Sparta for guidance and protection. Thus this single city became the foremost
power in southern Greece.
 "Pelops's island," a name derived from a
legendary hero who settled in southern Greece.
SPARTA A MILITARY CAMP
It is clear that the Spartans must have been an extremely
vigorous and warlike people. Their city, in fact, formed a military camp,
garrisoned by soldiers whose whole life was passed in war and in preparation
for war. The Spartans were able to devote themselves to martial pursuits
because they possessed a large number of serfs, called helots. The helots
tilled the lands of the Spartans and gave up to their masters the entire
product of their labor, except what was necessary for a bare subsistence.