Greece's geography was a large contributor to the lack of unification before 338 B.C. Because Greece is very mountainous and is separated by many rivers and other water bodies, the city-states that developed were geographically isolated and had little interaction with one another. Lack of communications led to the development of fierce rivalries between neighboring city-states. Without any reason to unite, the city-states stayed separate and continued to war with one another. However, when Philip II of Macedonia attempted to unite and take control of Greece, he became a common enemy for the Greek city-states to unite against. However, despite the alliances formed between the Greeks, Philip II was able to conquer Greece and unified the rest
