why was it important for citizens to participate in the assembly; what role did cleisthenes play in the development of greek democracy?; how did the peloponnesian war impact athens?; what advantage did the greek army have at the battle of marathon?; what advantage did athens have during the peloponnesian war?; the world's first democracy developed in the greek city-state of; what is a characteristic of an oligarchy?; how did the persian wars affect the greek army?