As a reaction to the overpopulation, economic problems, and rising political tension within Greece between 750 and 600 BC, many Greeks left the mainland by ship to establish new colonies. Some went freely to escape tensions, while others were sent as exiles. Any given expedition consisted of about 100-200 people, mostly young men, and was led by a Greek noble, searching to gain more power and wealth outside of Greece. A citizen who left Greece to go to one of these colonies gave up his Greek citizenship in exchange for citizenship in the new colony.
These colonies were widespread, and arose in places including southern Italy, Sicily, Sardinia, Corsica, the southern French coast, and the eastern Spanish coast, the coast of the Black Sea, and