The little City-States of Greece, as has just been said, were independent States, just like modern nations. While all the Greeks regarded themselves as tribes of a single family, descended from a common ancestor, Hellen, and the bonds of a common race, language, and religion tended to unite them into a sort of brotherhood, the different City-States were held apart by their tribal origins, by narrow political sympathies, and by petty laws. A citizen of one city, for example, was an alien in another, and could not hold property or marry in a city not his own. Such attitudes and laws were but natural, the time and age considered. Sometimes, in case of great danger, as at the time of the Persian invasions (492-479 B.C.), a number of the States would combine to form a defensive league; at other times they made war on one another. The federal principle, such as we know it in the United States in our state and national governments, never came into play. At different times Athens, Sparta, and Thebes aspired to the leadership of Greece and tried to unite the little States into a Hellenic Nation, but the mutual jealousies and the extreme individualism of the people, coupled with the isolation of the States and the difficulties of intercommunication through the mountain passes, stood in the way of any permanent union. [2] What Rome later accomplished with relative ease and on a large scale, Greece was unable to do on even a small scale. A lack of capacity to unite for coöperative undertakings seemed to be a fatal weakness of the Greek character. THE PEOPLE. The Greeks were among the first of the European peoples to attain to any high degree of civilization. Their story runs back almost to the dawn of recorded history. As early as 3500 B.C. they were in an advanced stone age, and by 2500 B.C. had reached the age of bronze. The destruction of Homer's Troy dates back to 1200 B.C., and the Homeric poems to 1100 B.C., while an earlier Troy (Schliemann's second city) goes back to 2400 B.C. This history concerns the mainland of Asia Minor. By 1000 B.C. the southern peninsula of Greece had been colonized, between 900 and 800 B.C. Attica and other portions of upper Greece had been settled, and by 650 B.C. Greek colonization had extended to many parts of the Mediterranean. [3]