The Greek polis was not the first form of city-state to emerge. The earliest states in Sumer were also city-states, as were many of the small Mycenaean kingdoms. What differentiated the new Greek model from older city-states was that the polis was more than a political institution — it was a community of citizens with their own customs and laws. With one exception, the poleis that emerged after 800 B.C.E. did not have kings but instead were self-governing. The physical, religious, and political forms of the polis varied from place to place, but everywhere it was relatively small, reflecting the fragmented geography of Greece. The very smallness of the polis enabled Greeks to see how they fit individually into the overall system, and thus how the individual parts made up the social whole.

The polis included a city and its surrounding countryside. The countryside was essential to the economy of the polis and provided food to sustain the entire population. The people of the polis typically lived in a compact group of houses within the city, which by the fifth century B.C.E. was generally surrounded by a wall. Another feature was a usually elevated area called the acropolis, where the people erected temples, altars, and public monuments. The polis also contained a public square or marketplace, the agora, where there were porticoes, shops, public buildings, and courts. The agora was the political center of the polis.

All poleis, with one exception, did not have standing armies. Instead they relied on their citizens for protection. Very rich citizens often served as cavalry, which was, however, never as important as the heavily armed infantrymen known as hoplites. These commoners were the backbone of the army, just as foot soldiers were in China during the Warring States Period (see Chapter 4).

Greek poleis had several different types of government. Sporadic periods of violent political and social upheaval often led to the seizure of power by one man, a type of government the Greeks called tyranny. Tyrants were not always oppressive rulers, however, and sometimes used their power to benefit average citizens.

Democracy was rule by citizens, not the people as a whole. Almost all Greek cities defined a citizen as an adult man with at least one citizen parent. Thus citizens shared ancestry as well as a place of residence. Women were citizens for religious and reproductive purposes, but their citizenship did not give them the right to participate in government. Free men who were not children of a citizen, known as resident foreigners, and slaves were not citizens and had no political voice.

Oligarchy was government by a small group of wealthy citizens. Many Greeks preferred oligarchy because it provided more political stability than did democracy. Although oligarchy was the government of the prosperous, it left the door open for political and social advancement. If members of the polis could meet property or money qualifications, they could enter the governing circle.