What was the structure and what were the main principles of each civilization's government in Ancient Greece and Ancient Rome

Ancient Greece:

Structure:
- Ancient Greece was comprised of city-states, each with its own government and laws. The two most prominent city-states were Athens and Sparta.
- Athens had a system of direct democracy, in which all male citizens could participate in the decision making process by voting on laws and policies at the Assembly. They also had a Council of 500, which proposed laws and policies to be voted on by the Assembly.
- Sparta, on the other hand, had an oligarchic system, with two kings serving as joint rulers and a Council of Elders (Gerousia) made up of 28 members who were elected for life.

Principles:
- Democracy: Athens is often considered the birthplace of democracy, as it was one of the first societies to allow citizens a voice in governance.
- Citizenship: In both Athens and Sparta, citizenship was reserved for free, native-born men who were over the age of 18.
- Rule of Law: The Greeks believed in the importance of laws that applied equally to all citizens, and that no one, not even rulers, were above the law.

Ancient Rome:
Structure:
- Ancient Rome started as a monarchy, with kings ruling the city-state. However, this was eventually replaced by a Republic in which power was divided among elected officials and a system of checks and balances were introduced.
- Roman society was governed by a Senate, made up of wealthy and powerful citizens who advised elected officials and played a significant role in decision making.
- Eventually, the Republic was replaced by an Empire, with an Emperor at the helm. The Emperor held supreme power and authority over all aspects of governance.

Principles:
- Republicanism: The Roman Republic was based on the principles of civic virtue, the rule of law, and individual rights. Citizens had a say in governance through the election of officials and the Senate.
- Imperialism: The Roman Empire expanded through conquest and colonization, ultimately ruling over a vast territory and diverse population.
- Centralized Authority: Under the Empire, power was consolidated in the hands of the Emperor, with a hierarchical system of governance that extended throughout the empire.