The Decline & fall of the Greek Polis (431-336 BCE)

If the Persian Wars were the great epic of Greek history, the century of conflict between Greek poleis from 431 to 338 B.C.E.. was its great tragedy.  During this time, the Greeks wasted their energies fighting one another and left the way open for an outside power, Macedon, to come in and take over.  There were three main lines of development that led to the final fall of the polis in the fifth and fourth centuries B.C.E.

Economic and military changes

First of all, the Persian wars exposed the Greeks to a wider world of trade as well as different military tactics that could threaten the powerful, but largely immobile hoplite phalanx.  Athens especially adapted to these new challenges, relying more on trade, foreign grain, and a money economy, along with the navy and Long Walls to protect its empire. Growing fear of Athens and the resulting Peloponnesian War would force other poleis to adapt in order to be able to compete with Athens.  Sparta, in particular, built a navy and, after the Peloponnesian War, relied increasingly on mercenaries to bolster its power.  In addition, lightly armed troops known as peltasts were used to give Greek armies more flexibility.
As a result, more and more Greeks were drawn from the countryside by the lure of riches to be made as traders and mercenaries.  Trade and a money economy grew in importance compared to the small family farms that had previously been the mainstay of the polis' economy.  Also, warfare became professional, sophisticated, chronic, and expensive.  This contrasted sharply with the previous style of cheap, amateur, and less destructive warfare waged by hoplite farmers over the last 250 years.  Rising taxes to support this new style of warfare put increasing burdens on the farmer hoplites who started to decline economically, militarily, and politically.  Gradually, large estates worked by tenant farmers or slaves would replace the small family owned farms worked by independent farmers.  And once these farmers, the backbone of the traditional polis, went into decline, so did the polis itself.  The Greeks were still a dynamic people, but the polis itself was starting to decay.

The spread of Greek civilization

 by way of its colonies to peoples outside of Greece triggered the second long term process affecting the polis.  Many of these people assumed at least a veneer of Greek culture and built quasi-Greek states that mimicked the Greeks in their organization, military institutions, and culture.  Most notable of these states was Macedon, a region to the north of Greece that had acted as a buffer against aggressive tribes further north.  In 359 B.C.E., one of these tribes, the Illyrians, killed a Macedonian king in battle.  It was his successor, Philip II, who would build a strong kingdom on the ruins of this disaster.  Like the economic changes then taking place, this spread of Greek civilization to Macedon would contribute to the downfall of the Greek polis.

Chronic warfare

, beginning with the Peloponnesian war, was the third reason for the decline of the polis.  There were three basic causes for this war which itself would trigger a self-destructive cycle.  First, there was a basic underlying fear other poleis had of the dominant Greek state, which at this time was Athens.  Second, there was the mutual hostility between individual poleis such as Corinth against Corcyra, Athens against Megara, and Thebes against Plataea.  Finally, there was a fatal flaw infecting Greek diplomacy at this time. Since most poleis were tied to either the Peloponnesian League (Sparta's alliance) or the Athenian Empire, any conflict between individual members of the opposing alliances could eventually drag the whole Greek world into a much larger and more destructive war.  It was such a flaw of interlocking alliances that would pull all of Europe and eventually much of the world into World War I in 1914. All these factors led to an unfortunate pattern of wars that also would eventually destroy the polis.  Triggering this pattern was a tendency of the poleis to gang up against the most powerful Greek state at that time.  This would bring about not only the downfall of that state, but also the rise of another polis to dominance, causing the other poleis to gang up on that state, and so on.  This cycle would repeat itself three times: first in the Peloponnesian War to bring down Athens, next in a series of wars that wrecked Sparta's power and brought Thebes to pre-eminence, and finally in the struggle against Thebes that would leave all of Greece open to attack by the growing Macedonian kingdom to the north.

Continuing warfare after the Peloponnesian War (404-355 B.C.E.)

We have already seen in detail how Sparta defeated Athens in the Peloponnesian War.  However, Sparta’s victory hardly meant peace for the Greek world.  Many of Athens' subjects had joined Sparta, believing they would be free to run their own lives.  Instead, the Spartans installed pro-Spartan oligarchies that were watched over by Spartan governors and garrisons in many poleis.  Sparta also failed to turn over Ionia to Persia in return for its aid against Athens.  Naturally, such high-handed actions angered both Persia and most other Greeks.  Leading the way were the Athenians who replaced the Spartan backed and repressive oligarchy of The Thirty with a new democracy.
All this led to the Corinthian War (395-387 B.C.E.).  The Spartans in Ionia could more than hold their own against the Persian forces there.  However, what Persian armies could not accomplish, Persian gold could by funding Athens, Thebes, and Corinth against Sparta, which drew the Spartan forces out of Ionia and back to Greece.  Persia also gave Athens a navy that crushed the Spartan fleet, sailed to Athens, and oversaw the rebuilding of the Long Walls.  Sparta's gains from the Peloponnesian War were quickly slipping away.
Faced with such a powerful coalition, Sparta made peace with Persia, handing Ionia over in return for help against the other Greeks.  In 387 B.C.E. Persia dictated a treaty called the King's Peace to all the Greeks, taking Ionia for itself, and putting its ally Sparta back on top of the Greek world.  The irony of it all was that the Persians, without striking a blow, had accomplished what Xerxes' huge army had failed to do a century before.
Naturally, the Greeks, did not abide by this decision for long, with Thebes and Athens leading the resistance against Sparta.  The Thebans drove the Spartan garrison from their citadel and formed the Boeotian League in direct defiance of Sparta and the King's Peace.  At Leuctra in 37l B.C.E...,he Theban general, Epaminondas stacked one flank of his phalanx 50 ranks deep, crushed the opposing Spartan wing, and then rolled up the rest of their army.  A similar battle at Mantinea nine years later destroyed the mystique of Spartan invincibility, and with it most of Sparta's power and influence.  Unfortunately for Thebes, Epaminondas was killed, and with him died Thebes' main hope to dominate the Greek world..
Meanwhile, the Athenians had formed a second Delian League with various Aegean states, promising to treat them better than they had treated the first Delian League. But Athens soon reverted to its old imperialist behavior.  This triggered a revolt known as the Social War that ended Athens' imperial ambitions once and for all.  Thus by 355 B.C.E., after 75 years of almost constant warfare, Athens' empire was gone, Sparta's army and reputation were wrecked, and Thebes' hopes for dominance were virtually laid to rest with Epaminondas.  The polis' resulting exhaustion combined with the long-range forces undermining the polis due to the Persian Wars and Greek colonization left the polis was in serious decline opened the way for a new power to step in.

The rise of Macedon (355-336 B.C.E.)

Macedon was a country north of Greece inhabited by tribes speaking a dialect related to Greek.  While the Greeks considered them barbarians, the Macedonians liked to think of themselves as Greeks, and had played a minor role in Greek history from time to time.  However, Macedon had never been a strong power until Philip II came to the throne in 359 B.C.E. after invading tribes from the north had killed his predecessor.
Philip was one of the most remarkable figures in Greek history, only being overshadowed by his son Alexander.  He was a shrewd, ambitious, and unscrupulous politician who knew how to exploit the hopes, fears, and mutual hatreds of the Greeks to his own advantage.  The key to much of Philip's success was control of the gold mines of Amphipolis, which gave him the money to do three things: build roads to tie his country together, bribe Greek politicians, and build up his army.  Philip was an outstanding organizer and general who built what was probably the best army up to that point in history.  Its main striking arm was an excellent cavalry, but it also utilized a phalanx armed with thirteen-foot long pikes (spears) and lightly armed peltasts.  Together, these gave him the flexibility and coordination to deal with almost any situation on a battlefield.
Preferring diplomacy to fighting whenever possible, Philip was able to work his way into the confidence of various Greek states to undermine their resistance to him when he finally decided to strike.  For example, he gained a foothold in Greece by defending Delphi from another city-state, Phokis.  He also undermined Athens' power by taking and then freeing one of its allies and posing as the champion of all Greek liberties.  Bit by bit, Philip worked his way southward, with only a few Greeks recognizing what was happening.  Among these was Demosthenes, probably the greatest orator of the ancient world.  In a masterful series of speeches known as Philippics, he repeatedly warned the Athenians of the danger to the north, but they did little.
Historians through the ages have blamed the Athenians for their failure to react well to the Macedonian threat.  However, in all fairness, the Athens faced a difficult dilemma, since acting against Philip could have been as ruinous as not moving to stop him.  On the one hand, failing to act against Philip would allow him to conquer Greece.  However, on the other hand, without an empire to provide it with the full treasury it had the previous century, Athens could no longer sustain a prolonged war against such a power as Macedon.  Therefore, fighting such a war very likely would have wrecked Athens' finances and given Philip the victory anyway.
Athens and Thebes did finally band together to meet the Macedonians at Chaeronea in 338 B.C. A tricky back-stepping maneuver by the Macedonian phalanx lured the Athenians out of position, exposing the Thebans to the decisive cavalry charge led by Philip's eighteen-year old son, Alexander.  Demosthenes and others fled the field, leaving their shields and Greek liberty in the dust.  For all intents and purposes, the age of the Greek polis was dead.  The age of Alexander the Great and the Hellenistic kingdoms was about to dawn.