How do classical Greek political structures compare with those of classical Rome

The ancient Roman and Greek civilizations had well-organized political processes that greatly influenced the manner in which later governments were structured in Europe and the United States. The system of political parties, the establishment of divisions in government - - even political words such as democracy, monarchy and tyranny - - originated in ancient Rome and Greece. Although Rome drew many of its political principles from the Greeks, and as a result, developed a government similar to that of Greece, there were several differences between the two.