Final answer:
The major cause of the Peloponnesian War was the power struggle between Athens and Sparta. Athens' growing power and influence, as well as the establishment of the Delian League, were seen as threats by Sparta and its allies. The war had significant political, cultural, and social consequences for Greece.
Step-by-step explanation:
The major cause of the Peloponnesian War was the power struggle between Athens and Sparta, the two most prominent city-states in ancient Greece. Sparta, a conservative and militaristic city-state, viewed Athens' growing power and influence as a threat to its own dominance and the traditional Greek way of life. Tensions between the two city-states escalated over time, leading to a full-scale war that lasted for decades.
One of the key events that triggered the war was Athens' establishment of the Delian League, an alliance of Greek city-states, which gradually transformed into an empire under Athenian control. Sparta and its allies, feeling threatened by Athens' growing empire and influence, formed the Peloponnesian League to counterbalance Athenian power.
The war had significant political, cultural, and social consequences for Greece. It weakened both Athens and Sparta, allowing other city-states like Thebes to rise in power. The war also changed the dynamics of Greek society, with more reliance on professional armies and mercenaries rather than citizen-soldiers. Additionally, the war marked a shift in Greek mindset, as they began to look beyond Greece and embrace a more cosmopolitan outlook.