Delian League The Delian League , founded in 478 BC , was an association of Greek city - states , members numbering between 150 to 173 , under the leadership of Athens , whose purpose was to continue fighting the Persian Empire after the Greek victory in the Battle of Plataea at the end of the Second Persian invasion of Greece . The League ' s modern name derives from its official meeting place , the island of Delos , where congresses were held in the temple and where the treasury stood until , in a symbolic gesture , Pericles moved it to Athens in 454 BC . Shortly after its inception , Athens began to use the League ' s navy for its own purposes . This behavior frequently led to conflict between Athens and the less powerful members of the League . By 431 BC , Athens ' heavy - handed control of the Delian League prompted the outbreak of the Peloponnesian War ; the League was dissolved upon the war ' s conclusion in 404 BC . Background . The Greco - Persian Wars had their roots in the conquest of the Greek cities of Asia Minor , and particularly Ionia , by the Achaemenid Persian Empire of Cyrus the Great shortly after 550 BC . The Persians found the Ionians difficult to rule , eventually settling for sponsoring a tyrant in each Ionian city . While Greek states had in the past often been ruled by tyrants , this was a form of arbitrary government that was on the decline . By 500 BC , Ionia appears to have been ripe for rebellion against these Persian clients . The simmering tension finally broke into open revolt due to the actions of the tyrant of Miletus , Aristagoras . Attempting to save himself after a disastrous Persian - sponsored expedition in 499 BC , Aristagoras chose to declare Miletus a democracy . This triggered similar revolutions across Ionia , extending to Doris and Aeolis , beginning the Ionian Revolt . The Greek states of Athens and Eretria allowed themselves to be drawn into this conflict by Aristagoras , and during their only campaigning season ( 498 BC ) they contributed to the capture and burning of the Persian regional capital of Sardis . After this , the Ionian revolt carried on ( without further outside aid ) for a further five years , until it was finally completely crushed by the Persians . However , in a decision of great historic significance , the Persian king Darius the Great decided that , despite successfully subduing the revolt , there remained the unfinished business of exacting punishment on Athens and Eretria for supporting the revolt . The Ionian revolt had severely threatened the stability of Darius ' s empire , and the states of mainland Greece would continue to threaten that stability unless dealt with . Darius thus began to contemplate the complete conquest of Greece , beginning with the destruction of Athens and Eretria . In the next two decades there would be two Persian invasions of Greece , occasioning , thanks to Greek historians , some of the most famous battles in history . During the first invasion , Thrace , Macedon and the Aegean Islands were added to the Persian Empire , and Eretria was duly destroyed . However , the invasion ended in 490 BC with the decisive Athenian victory at the Battle of Marathon . Between the two invasions , Darius died , and responsibility for the war passed to his son Xerxes I . Xerxes then personally led a second Persian invasion of Greece in 480 BC , taking an enormous ( although oft - exaggerated ) army and navy to Greece . Those Greeks who chose to resist ( the ' Allies ' ) were defeated in the twin simultaneous battles of Thermopylae on land and Artemisium at sea . All of Greece except the Peloponnesus thus having fallen into Persian hands , the Persians then seeking to destroy the Allied navy once and for all , suffered a decisive defeat at the Battle of Salamis . The following year , 479 BC , the Allies assembled the largest Greek army yet seen and defeated the Persian invasion force at the Battle of Plataea , ending the invasion and the threat to Greece . The Allied fleet defeated the demoralized remnants of the Persian fleet in the Battle of Mycale — on the same day as Plataea , according to tradition . This action marks the end of the Persian invasion , and the beginning of the next phase in the Greco - Persian wars , the Greek counterattack . After Mycale , the Greek cities of Asia Minor again revolted , with the Persians now powerless to stop them . The Allied fleet then sailed to the Thracian Chersonese , still held by the Persians , and besieged and captured the town of Sestos . The following year , 478 BC , the Allies sent a force to capture the city of Byzantion ( modern day Istanbul ) . The siege was successful , but the behaviour of the Spartan general Pausanias alienated many of the Allies , and resulted in Pausanias ' s recall . Formation of the League . After Byzantion , Sparta was eager to end its involvement in the war . The Spartans were of the view that , with the liberation of mainland Greece , and the Greek cities of Asia Minor , the war ' s purpose had already been reached . There was also perhaps a feeling that establishing long - term security for the Asian Greeks would prove impossible . In the aftermath of Mycale , the Spartan king Leotychides had proposed transplanting all the Greeks from Asia Minor to Europe as the only method of permanently freeing them from Persian dominion . Xanthippus , the Athenian commander at Mycale , had furiously rejected this ; the Ionian cities were originally Athenian colonies , and the Athenians , if no - one else , would protect the Ionians . This marked the point at which the leadership of the Greek alliance effectively passed to the Athenians . With the Spartan withdrawal after Byzantion , the leadership of the Athenians became explicit . The loose alliance of city states which had fought against Xerxes ' s invasion had been dominated by Sparta and the Peloponnesian league . With the withdrawal of these states , a congress was called on the holy island of Delos to institute a new alliance to continue the fight against the Persians ; hence the modern designation " Delian League " . According to Thucydides , the official aim of the League was to " avenge the wrongs they suffered by ravaging the territory of the king . " In reality , this goal was divided into three main efforts — to prepare for future invasion , to seek revenge against Persia , and to organize a means of dividing spoils of war . The members were given a choice of either offering armed forces or paying a tax to the joint treasury ; most states chose the tax . League members swore to have the same friends and enemies , and dropped ingots of iron into the sea to symbolize the permanence of their alliance . The Athenian politician Aristides would spend the rest of his life occupied in the affairs of the alliance , dying ( according to Plutarch ) a few years later in Pontus , whilst determining what the tax of new members was to be . Composition and expansion . In the first ten years of the league ' s existence , Cimon / Kimon forced Karystos in Euboea to join the league , conquered the island of Skyros and sent Athenian colonists there . Over time , especially with the suppression of rebellions , Athens exercised hegemony over the rest of the league . Thucydides describes how Athens ' s control over the League grew : Rebellions . Naxos . The first member of the league to attempt to secede was the island of Naxos in c . 471 BC . After being defeated , Naxos is believed ( based on similar , later revolts ) to have been forced to tear down its walls , and lost its fleet and its vote in the League . Thasos . In 465 BC , Athens founded the colony of Amphipolis on the Strymon river . Thasos , a member of the League , saw her interests in the mines of Mt . Pangaion threatened and defected from the League to Persia . She called to Sparta for assistance but was denied , as Sparta was facing the largest helot revolution in its history . An aftermath of the war was that Cimon was ostracised , and the relations between Athens and Sparta turned hostile . After a three - year siege , Thasos was recaptured and forced back into the League . The siege of Thasos marks the transformation of the Delian league from an alliance into , in the words of Thucydides , a hegemony . After two years Thasos surrendered to the Athenian leader Cimon . In result , the fortification walls of Thasos were torn down , their land and naval ships were confiscated by Athens . The mines of Thasos were also turned over to Athens , and they had to pay yearly tribute and fines . Policies of the League . In 461 BC , Cimon was ostracized and was succeeded in his influence by democrats such as Ephialtes and Pericles . This signaled a complete change in Athenian foreign policy , neglecting the alliance with the Spartans and instead allying with her enemies , Argos and Thessaly . Megara deserted the Spartan - led Peloponnesian League and allied herself with Athens , allowing construction of a double line of walls across the Isthmus of Corinth and protecting Athens from attack from that quarter . Around the same time , due to encouragement from influential speaker Themistocles , the Athenians also constructed the Long Walls connecting their city to the Piraeus , its port , making it effectively invulnerable to attack by land . In 454 BC , the Athenian general Pericles moved the Delian League ' s treasury from Delos to Athens , allegedly to keep it safe from Persia . However , Plutarch indicates that many of Pericles ' rivals viewed the transfer to Athens as usurping monetary resources to fund elaborate building projects . Athens also switched from accepting ships , men and weapons as dues from league members , to only accepting money . The new treasury established in Athens was used for many purposes , not all relating to the defence of members of the league . It was from tribute paid to the league that Pericles set to building the Parthenon on the Acropolis , replacing an older temple , as well as many other non - defense related expenditures . The Delian League was turning from an alliance into an empire . Wars against Persia . War with the Persians continued . In 460 BC , Egypt revolted under local leaders the Hellenes called Inaros and Amyrtaeus , who requested aid from Athens . Pericles led 250 ships , originally intended to attack Cyprus , to their aid because it would further damage Persia . After four years , however , the Egyptian rebellion was defeated by the Achaemenid general Megabyzus , who captured the greater part of the Athenian forces . In fact , according to Isocrates , the Athenians and their allies lost some 20 , 000 men in the expedition . The remainder escaped to Cyrene and thence returned home . This was the Athenians ' main ( public ) reason for moving the treasury of the League from Delos to Athens , further consolidating their control over the League . The Persians followed up their victory by sending a fleet to re - establish their control over Cyprus , and 200 ships were sent out to counter them under Cimon , who returned from ostracism in 451 BC . He died during the blockade of Citium , though the fleet won a double victory by land and sea over the Persians off Salamis , Cyprus . This battle was the last major one fought against the Persians . Many writers report that a peace treaty , known as the Peace of Callias , was formalized in 450 BC , but some writers believe that the treaty was a myth created later to inflate the stature of Athens . However , an understanding was definitely reached , enabling the Athenians to focus their attention on events in Greece proper . Wars in Greece . Soon , war with the Peloponnesians broke out . In 458 BC , the Athenians blockaded the island of Aegina , and simultaneously defended Megara from the Corinthians by sending out an army composed of those too young or old for regular military service . The following year , Sparta sent an army into Boeotia , reviving the power of Thebes in order to help hold the Athenians in check . Their return was blocked , and they resolved to march on Athens , where the Long Walls were not yet completed , winning a victory at the Battle of Tanagra . All this accomplished , however , was to allow them to return home via the Megarid . Two months later , the Athenians under Myronides invaded Boeotia , and winning the Battle of Oenophyta gained control of the whole country except Thebes . Reverses followed peace with Persia in 449 BC . The Battle of Coronea , in 447 BC , led to the abandonment of Boeotia . Euboea and Megara both revolted , and while the former was restored to its status as a tributary ally , the latter was a permanent loss . The Delian and Peloponnesian Leagues signed a peace treaty , which was set to endure for thirty years . It only lasted until 431 BC , when the Peloponnesian War broke out . Those who revolted unsuccessfully during the war saw the example made of the Mytilenians , the principal people on Lesbos . After an unsuccessful revolt , the Athenians ordered the death of the entire male population . After some thought , they rescinded 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 besieged and conquered ; the males were put to death and the women sold into slavery ( see Melian dialogue ) . The Athenian Empire ( 454 – 404 BC ) . By 454 , the Delian League could be fairly characterized as an Athenian Empire ; at 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 secede 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 Ionia to revolt . Athens was eventually still able to suppress these revolts . To further strengthen Athens ' grip on its empire , Pericles in 450 began a policy of establishing " cleruchiai " — quasi - colonies that remained tied to Athens and which served as garrisons to maintain control of the League ' s vast territory . Furthermore , Pericles employed a number of offices to maintain Athens ' empire : " proxenoi " , who fostered good relations between Athens and League members ; " episkopoi " and " archont es " , who oversaw the collection of tribute ; and " hellenotamiai " , who received the tribute on Athens ' behalf . Athens ' s empire was not very stable and after only 27 years of war , the Spartans , aided by the Persians and internal strife , were able to defeat it . However , it did not remain defeated long . The Second Athenian Empire , a maritime self - defense league , was founded in 377 BC and was led by Athens . Athens would never recover the full extent of her power , and her enemies were now far stronger and more varied .