"Some people believe that ancient Athens was an enlightened democracy, filled with scholars and philosophers, much like a modern-day Western civilization. Such people have never heard of the Athenian Empire."
The Athenian Empire
In 478 BC, following the defeat of Xerxes invasion of Greece, Pausanias the Spartan led Hellenic forces against the Persians. He was an unpopular commander (who may have conspired with the Persians), and Sparta was eager to stop prosecuting the war. They surrendered the leadership of the ongoing campaign to Athens, which was eager to accept it. The Delian league was inagurated in 477 BC as an offensive and defensive alliance against Persia. The principle cities in the Delian League were Athens, Chios, Samos, and Lesbos, but many of the principle islands and Ionian cities joined the league.
Athens led the Delian League from the begining, though at its founding the treasury was located on the island of Delos, and each state in the league had an equal vote. The assesment due from each state was assigned by Aristides the Just, leader of the Athenians; some members were assessed ships, others money. A council of all the cities met at Delos regularly, probably when bringing their assessment to the island.
The first action of the Delian League was the capture of Eion, a Persian fortification that guarded a river crossing on the way to Asia; following this victory, the League acted against several pirate islands in the Aegean Sea, most notably against Scyrus where they turned the Dolopian inhabitants in to slaves and set up a Cleruchy. These actions were most likely very popular with the League.
However, the League, particuarly the Athenians, were willing to force cities to join the League. Carystus, a city on the southern tip of Euboea, was forced to join the League by military actions of the Athenians. The justification for this was that Carystus was enjoying the advantages of the League (protection from pirates and the Persians) without taking on any of the responsibilities. Furthermore, Carystus was a traditional base for Persian occupations. Naxos, a member of the Delian League, attempted to seceed, and was enslaved; Naxos is believed to have been forced to tear town her walls, lost her fleet, and her vote in the League.
Thucydides tells us that this is how Athens control over the League grew.
Of all the causes of defection, that connected with arrears of tribute and vessels, and with failure of sevice, was the chief; for the Athenians were very severe and exacting, and made themselves offensive by applying the screw of necessity to men who were not used to and in fact not disposed for any continuous labour. In some other respects the Athenians were not the old popular rulers they had been at first; and if they had more than their fair share of service, it was correspondingly easy for them to reduce any that tried to leave the confederacy. For this the allies had themselves to blame, the wish to get off service making most of them arrange to pay their share of the expense in money instead of in ships, and so to avoid having to leave their homes. Thus while Athens was increasing her navy with the funds they contributed, a revolt always found them without resources or experience for war. [Thucydides i. 99]
In 454 BC, suppossedly due to an increase in Persian and priate activity, the Athenians moved the treasury of the League from Delos to Athens, further consolidating their control over the League. However, the Athenians continued to fight the forces of the Persian King. Sometime around 451 BC, Cimon launched his "last campaign". The details of this campaign are unclear; it appears that from 453 BC-451 BC, Athens and the League campaigned in Egypt against the Persians. In 451 BC, possibly continuing into 450 BC, the Athenians waged a campaign against the Persians by land and sea, destroying a Phonecian fleet and a Persian army, supposedly on the same day, in a climatic battle on the Eurymedon river in Asia. Following the defeat of the Persians, some authors report that Cimon pursued his enemies to Cyprus, where a battle was fought at Salamis. In any event, the events of 451 BC-450 BC led to a resounding defeat of the Persians, but Cimon did not survive them.
The battle of Eurymedon/Cyprus was the last major one fought against the Persians. It is unclear if the League (or the Athenians) signed a peace treaty with the Persians, but Cyprus was simply too far from Athens and too close to the centers of Persian power to be taken and held by the Athenians. Many writers report that the treaty, known as the Peace of Callias, was formalised in 450 BC; but some writers believe that the treaty was a myth created later to inflate the stature of Athens.
Under Pericles, who began to have influcence following the death of Cimon, matters in Greece began to occupy more of the Athenians attention. The Athenians began construction of the Long Walls to the sea. The contruction of these walls would eventually make Athens invulnerable to attack by land. The Lacedaemonians marhced against the Athenians, in part to delay the building of these walls, but were brought to battle at Tanagra. While the Spartans were victorious, they returned home, and the Athenians regrouped, later winning a victory against the allies of Sparta at Oenophyta.
During the next two decades, the Athenians continued to spar with the Peloponnesian League while enslaving the Delian League. Aegina, Euboea, Megara, Samos all revolted at varying times, and were reduced to tributary allies, or the islanders were slaughtered and replaced with Athenian citizens. Once subdued, few islanders dared to revolt again until the Pelponnessian War had turned decisively against the Athenians.
Those who revolted unsuccessfully during the war saw the example made of the Mitylenians, the principle people on Lesbos. After an unsuccessful revolt, the Athenians ordered the death of the entire male population. After some thought, they recinded this order, and only put to death the leading 1000 ringleaders of the revolt, and redistributed the land of the entire island to Athenian shareholders, who were sent out to reside on Lesbos.
This type of treatment was not reserved solely for those who revolted. Thucydides documents the example of Melos, a small island, neutral in the war, though originally founded by Spartans. The Melians were offered a choice to join the Athenians, or be conquered. Choosing to resist, their town was beseiged and conquered; the males were put to death, and the women sold into slavery.
The Delian League was never formally turned into the Athenian Empire; but by the start of the Peloponnesian War, only Chios and Lesbos were left to contribute ships, and these states were by now far too weak to seceed without support. Lesbos tried to revolt first, and failed completely. Chios, the greatest and most powerful of the original members of the Delian League (save Athens), was the last to revolt, and in the aftermath of the Syracusan Expedition enjoyed a success of several years, inspiring all of Iconia to revolt. Athens was, however, still able to eventually supress these revolts.
The Athenian Empire was very stable, and only 27 years of war, aided by the Persians and internal strife, were able to defeat it. The Athenian Empire did not stay defeated for long. The "Second Athenian Empire", a maritime self-defense league, was founded in 377 BC and was led by Athens; but Athens would never recover the full extent of her power, and her enemies were now far stronger and more varied.