The helot’s anxiety ridden situation led the Spartans to fear even their neighbors, who were often sticking their spoons in that pot to brew up trouble. So the Spartans started to set their military sights on neighboring states in the sixth century B.C. However, when they conquered their neighbor, Tegea, rather than annex their land and people, they set up a truce with them.
They demanded an alliance. This was a brilliant move on the part of Spartans. Because Tegea would follow Sparta in all its foreign relationships, including wars, and also would supply for Sparta with a fixed amount of soldiers and equipments.
Tegea would remain an independent state in the exchange. In the southern part of Greece Sparta had formed with a huge number of states in a short time and had become the major power in Greece when the Persians invaded in 490 B.C. Their power eclipsed that of even their powerful neighbor in the north, Athens.