The Peloponnesian War was a protracted conflict that took place from 431 to 404 BCE between the two leading city-states of ancient Greece: Athens and its empire, and Sparta and its Peloponnesian League. The war is primarily documented by the Athenian historian Thucydides, who provides a detailed account of its causes, events, and consequences. The conflict can be summarized through its main phases and key elements:

1. Origins and Causes: The war stemmed from rising tensions and competition between Athens, which had established a powerful naval empire following its success in the Persian Wars, and Sparta, the dominant land power in Greece. The immediate cause was a series of disputes involving smaller states allied with the two powers.
2. First Phase (Archidamian War, 431-421 BCE): Named after the Spartan king Archidamus II, this phase was characterized by annual Spartan land invasions of Attica (the region around Athens), while Athens used its naval superiority to raid the Peloponnesian coast. The strategy of Pericles, the Athenian leader, was to avoid land battles with the superior Spartan army, relying instead on the long walls connecting Athens to its ports to keep the city supplied. This phase ended with the signing of the Peace of Nicias in 421 BCE, which was intended to last 50 years but was never fully respected by either side.
3. Interlude: The peace proved unstable, with skirmishes and proxy wars continuing. A significant event during this period was the disastrous Sicilian Expedition (415-413 BCE), in which Athens attempted to conquer Syracuse in Sicily but faced a catastrophic defeat, severely weakening its military and financial resources.
4. Second Phase (Ionian or Decelean War, 413-404 BCE): Sparta, with financial support from Persia, built a fleet to challenge Athenian naval power and established a permanent fort at Decelea in Attica, further straining Athenian resources. The war expanded to include battles in the Aegean Sea and Ionia (Asia Minor).
5. Conclusion and Aftermath: The war concluded with the siege of Athens and its surrender in 404 BCE, following the decisive Spartan victory at the Battle of Aegospotami in 405 BCE, where the Athenian fleet was destroyed. Sparta imposed harsh terms on Athens, dismantling its empire, tearing down its walls, and installing a pro-Spartan oligarchic government (the Thirty Tyrants).

The Peloponnesian War marked a significant shift in the balance of power in ancient Greece, leading to the decline of Athens as a major power and the temporary ascendance of Sparta. However, the conflict also weakened the overall Greek world, making it more susceptible to external powers, notably Macedon, in the following centuries. The war demonstrated the destructive potential of prolonged conflict among the Greek city-states and is often cited as a cautionary tale of the dangers of imperial overreach and the fragility of democratic institutions.

Summarize the Peloponnesian War for me.

The phrase “ancient Greek empire” might be misleading, as ancient Greece was not a single empire but rather a collection of independent city-states (poleis) such as Athens, Sparta, Corinth, and Thebes, among others. These city-states shared a common language and culture, but they were often rivals rather than united under a single government. However, there were periods during which certain states or alliances dominated the Greek world, notably during the Athenian Empire in the 5th century BCE and the Macedonian Empire under Alexander the Great in the late 4th century BCE.

The decline of Greek dominance in the ancient world can be attributed to a combination of internal conflicts, external pressures, and shifts in power dynamics, rather than a single “fall” as experienced by empires like Rome. Key factors include:

1. Peloponnesian War (431-404 BCE): This devastating conflict between Athens and Sparta and their respective allies weakened many Greek city-states, both economically and militarily. Athens’ defeat marked the end of its golden age and shifted power to Sparta, but Sparta was unable to maintain dominance for long.
2. Rise of Macedon: The power vacuum and general weakening of the Greek city-states allowed for the rise of Macedon under Philip II, who conquered and united most of Greece by 338 BCE after the Battle of Chaeronea. His son, Alexander the Great, extended Macedonian dominance by creating an empire that stretched from Greece to Egypt and into India but did not focus on consolidating Greek power within Greece itself.
3. Wars of the Diadochi: After Alexander’s death in 323 BCE, his generals (the Diadochi) fought among themselves for control of the empire, leading to its division and the establishment of Hellenistic kingdoms. While Greek culture spread across these kingdoms, the political unity and strength of the Greek city-states themselves further diminished.
4. Roman Conquest: The Hellenistic kingdoms eventually came into conflict with the expanding Roman Republic. Greece itself became embroiled in these conflicts, with the decisive Battle of Corinth in 146 BCE marking the end of Greek political independence and the beginning of Roman hegemony over Greece.
5. Cultural and Administrative Changes: Under Roman rule, Greece became a key part of the Roman Empire, and Greek culture greatly influenced Roman culture. However, the political and military power of the Greek city-states and kingdoms was effectively ended, and Greece was absorbed into the larger Roman, and later Byzantine, worlds.

Thus, the decline of Greek dominance was not due to the fall of a single “ancient Greek empire” but rather the result of centuries of warfare, shifting alliances, and the eventual rise of Rome as the dominant power in the Mediterranean.