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For the better part of a hundred years, Athens commanded an empire to be reckoned with. But the Parthenon and every other emblem of the polis’s greatness rested on a watery foundation: the navy.

In the fifth century B.C., Athens created the first great naval-based empire. For modern students of sea power, this almost accidental development provides valuable guidance in understanding both the utility of sea power and the dangers of overreliance on this one factor.

The roots of the Athenian Empire lay in an earlier event in Greek history. In 499 B.C., the Greek states on the western seaboard of Asia Minor rebelled against their Persian overlord and sent an envoy to implore the aid of Sparta, the balance wheel of the Greek state system, which usually answered cries for help. Unfortunately the envoy made the mistake of showing the Spartans a map of the world, a novel invention to them; when they discovered that the Persian capital was a three-month march inland, they bade him be gone by nightfall. At Athens, on the other hand, the envoy secured the support of the nascent Athenian democracy; Herodotus wryly deduced that “it seems indeed to be easier to deceive a multitude than one man.” The Athenians sent 20 warships, and neighboring Eritrea added four. With this aid the rebels sacked the Persian regional center of Sardis, but then the Athenians withdrew. It may be reckoned the first of a train of events that were to lead to remarkable results.

After initial successes, the Ionian rebels had to face the full might of Persia, which, like all empires, took time to assemble its forces, including a fleet provided by the Phoenicians. For the first time in Aegean history, a sea battle was the decisive turning point: In 495 B.C., off Lade, the league navy was defeated. The Persians took Miletus, on the coast of Asia Minor, early the next year and destroyed it as an object lesson. To punish the Athenians for their aid, a small amphibious force was dispatched in 490 B.C. straight across the Aegean. The Athenians dared not try to meet it on the sea even though it was encumbered by horse transports, but at Marathon on the east coast of Attica secured a great victory by land. The Spartans, who had promised assistance, were delayed by a religious festival and arrived only after the battle was over, to marvel at the Persian dead. The Greek world could venture to feel that the Medes, as the Persians were often called, were not invincible.

Then the Persian ruler Darius died, and his son Xerxes had to spend several years consolidating his rule before he could return to the Greek problem. This time Xerxes majestically decided to lead the expedition himself and gain military glory. So a huge army and navy, twice the size of any force the Greeks could field, was assembled in Asia Minor during the fall of 481 B.C.

By this time two events had taken place at Athens. The first was the discovery of a very rich lode in the state silver mines of Laurium. Normally the revenues were divided among the citizenry, but not this time. For, secondly, Themistocles had become undisputed leader of Athens by ostracizing his opponents; praised by Thucydides as a man who “could best divine what was likely to happen in the remotest future,” he persuaded his fellow citizens to use the money to build the first major Athenian fleet, 200 triremes in all, and begin fortifying the port of Piraeus as a base. As Thucydides sums up Themistocles’ policy, “It was he who first ventured to tell the Athenians that their future was on the sea.”

The trireme had by now become the standard type of warship in Mediterranean fleets, a wooden galley 200 feet long, propelled in battle by 170 inboard rowers arranged in staggered groups of three. A trireme is better compared to a racing shell than to a battleship; it was not very seaworthy, and usually fleets tried to land on friendly shores at night so the crews could rest and eat in greater comfort. In battle at sea, however, a trireme had one decisive advantage: In effect it was a man-driven torpedo whose bronze ram could be aimed with precision to puncture an enemy hull. Galleys thus remained dominant across ancient and medieval times until sailing ships were equipped with cannon for attack from a distance.

To realize how amazing the Athenian decision was, one must remember that while Athenian commerce and industry had been steadily advancing across the previous century, the state had played almost no role on the sea. In a conflict with the neighboring island of Aegina, the Athenians had had to buy triremes from Corinth and even so did poorly. Much later, in the Peloponnesian War, the Syracusan leader Hermocrates observed that “in fact the Athenians were more landsmen than the Syracusans and had taken to the sea only when forced to do so by the Persians.” Accidents can have mighty effects in shaping the course of history.

The Greek states that refused to surrender comprised only a small fraction of the multitude of small Hellenic countries, but they drew the proper lesson from the earlier dissensions of the Ionian rebels and concentrated command by land and by sea in the hands of Spartan leaders. In the spring of 480 B.C., they met at the Isthmus of Corinth to concert their resistance. The Peloponnesians insisted on building a wall across the isthmus itself, a naive plan that quite overlooked the fact that the Persian fleet could outflank its defense and the likelihood that Argos, which had remained neutral out of hostility to Sparta, would join the Persians as soon as they drew near.

Themistocles analyzed matters quite differently. The Persian army numbered perhaps 180,000 men, but in open battle its lightly equipped battalions were no match for the disciplined phalanxes of Greek spearmen. On the sea, conditions were less favorable: The Persian navy had over 600 warships; the backbone consisted of the Phoenician contingents, far more skilled than the Greeks in rowing techniques. Yet Themistocles spotted a serious weakness in the Persian plan of invasion: The army was so large that it had to move close to shore to receive seaborne grain; the navy in turn hugged the coast to protect the supply vessels. If only the Greeks could defeat the Persian navy, Xerxes’ army would be a less serious threat.

To secure the proper conditions for naval victory, two steps were necessary. First, the maritime powers among the Greek allies, especially Athens, would have to concentrate all their energies on the sea. Second, the Greek admirals would have to inveigle the superior Persian navy into narrow waters, where its numbers and the skill of the Phoenician galleys would be less effective. By dextrous argument Themistocles secured agreement that the Greeks would send their naval forces north with a small army to delay and, if possible, cripple the enemy.

Accordingly, Greek land forces occupied the narrow pass at Thermopylae between sea and mountains; the other routes from Thessaly south into Boeotia lay so far inland that the Persian strategic necessity of keeping army and navy together prevented their use. Off Thermopylae lay the island of Euboea, which would force the Persian navy into a narrow strait; to block its entry, the Greek fleet anchored at the northern end of the strait, at Artemisium, while a minor detachment guarded its southern exit. The Spartan admiral Eurybiades had most of the Athenian and other naval contingents, numbering 271 triremes in the main fleet.

Meanwhile the mighty panoply of Xerxes made its way slowly down into Greece. Everywhere along the way, the native peoples and states surrendered. But as Xerxes approached Thermopylae, his fleet encountered a violent storm that raged for three days and sank many ships; the Greek forces, in the sheltered lee of Euboea, were not damaged. The enemy navy suffered further damage when Xerxes sent a large detachment around Euboea to bottle up the Greek fleet, for another storm blew the 200 Persian ships of this flotilla onto the rocks of the island.

The main fleet then fought three battles with the Greeks off Artemisium, but neither side could secure a decisive victory. While his fleet was trying to force a passage by sea, Xerxes also launched an attack by land at the defenders of the narrow pass of Thermopylae. For two days his Persian “immortals” died in droves before the stern Greek lines; but on the second night a local traitor revealed the existence of a trail up the mountains behind the Greeks. The movement of the Persian flanking force was detected by the Spartan general Leonidas in time to send off most of his army; he and his Spartans sacrificed themselves to delay the main Persian thrust. The Greek navy had no recourse but to retreat to the island of Salamis, off Attica.

The Greeks could gain comfort from their success in whittling down the enemy navy; yet as their council of war met on the shore of Salamis, they could see smoke spiraling up from the Acropolis of Athens, where the Persians had quickly overcome the resistance of the priests and set fire to the temple roofs. All other Athenians had abandoned their homes and were now on the island of Salamis or at Troezen in the Peloponnese.

Some of the Greek admirals wished to withdraw to the Isthmus of Corinth and anchor off its wall. Themistocles argued that the only Greek hope lay in sticking to the main strategy of naval action. In response to a taunt that he no longer had a country or a right to speak, he threatened to sail off with the Athenian ships and citizens to found a new state in the western Mediterranean. Since the Greeks had no chance without the Athenian navy, they agreed to hold their position.

When dissension arose again in the Greek naval command, the wily Themistocles sent a trusted slave, Sicinnus, to the Persians to tell Xerxes that the Greeks were quarreling, that the Athenians were willing to turn traitor, and that if he wanted a great victory he needed only to attack. Xerxes fell into the trap and ordered his fleet to advance for the final blow; to make victory doubly sure, he sent a detachment around to the west end of the strait to bottle up the Greeks. Then he settled himself upon a throne on a hill overlooking the scene so he could award prizes to his most valorous subjects.

On a morning in late September, the Persian fleet, now reduced to some 350 ships, rowed in a line abreast from its anchorage on the Attic shore toward Salamis. The Greeks, who had about 300 ships in the action, knew they were encircled from the rear and, embarking Athenian hoplites on the ships, prepared for the decisive battle. As the Peisians closed in, their line was split by the little island of Psyttalia. Their confusion was heightened by the apparent retreat of the Greeks, who backed water on seeing the Persians enter the narrow reaches of the bay. This, however, was a maneuver designed to suck the enemy farther in; suddenly the Greeks rowed forward from front and flanks and plunged into hand-to-hand battle with the Persians.

By the close of the day, the despondent Xerxes could see his remaining ships rowing away in utter defeat. Some 200 Persian warships, mostly of the Phoenician contingent, were lost, as against only about 40 Greek ships.

Xerxes struck his tents and returned speedily to Asia Minor. Since the Persians could no longer be sure of supplies by sea, he also took back much of his army. As has usually been the case in history, the proper use of sea power can facilitate victory, but the final step must come by land. At Plataea the next year (479 B.C.), the allied army under Spartan command was equal in strength to the Persian force and routed it in a very untidy battle.

Salamis made possible the almost unbelievable Greek deliverance, and Themistocles was the indomitable agent who helped engineer the success. True, others had a hand in the glorious days of 480-479 B.C.: The Spartans provided leadership, which the allies accepted without demur; and after the battle of Salamis, it was the Aeginetans who got first prize for their role. But it was the Athenians who were to capitalize on the Greek success by moving steadily if unintentionally to consolidate the first great thalassocracy, or naval empire, one of the most productive and important in Western history. In this development Themistocles played no part; he soon fell victim to the bitter fights of Athenian politics and eventually wound up a pensioner of the Persian king in Asia Minor.

The Spartans, having done their duty in 480—479 B.C., were ready to stop; to counter the strong possibility that the Persians would regroup, as they had in the Ionian revolt, the Spartans suggested moving the people of the cities on the coast of Asia Minor to the Greek mainland. The Ionians were reluctant to leave the homes and graves of their ancestors, and Athens stepped forward, willing to serve as the leader in taking revenge on the Persians and securing the liberty of the Aegean states.

A number of Asiatic and island states met at the sacred island of Delos in the summer of 477 B.C. and formed a league. Each state was to provide warships or, in the case of smaller states, cash to help defray the expenses of war. Leadership was voluntarily assumed by Athens, which would furnish admirals (and the largest fleet), treasurers, and presidents of the league assembly. In flamboyant fashion the allies threw lumps of iron into the sea and swore to remain united until the iron floated; but probably none of them really expected lasting military involvement.

Athens duly marshaled Greek strength to sweep the Persians out of the Aegean and then the south coast of Asia Minor, also largely occupied by Greek states. The greatest triumph was Cimon’s destruction of the renascent Persian fleet at the battle of the Eurymedon River, early in the 460s B.C.

By this time the nature of the Delian League was subtly altering. When the small state of Carystus on the island of Euboea had been liberated, it had been forced to join the league; the crusade must not be weakened by local unwillingness to participate. Soon the island of Naxos grew weary of the annual burden of providing ships, but Athens quickly compelled it to resume its role in the common effort. Worst of all was the “revolt” in 464 B.C. of Thasos, a large state, which had to be recalled to its fealty by a siege.

Voluntary league, in sum, was slowly, almost unconsciously, becoming empire. Modern students date the point at which the process was complete to 454 B.C., when the league’s treasury, until then safeguarded at the Temple of Apollo on Delos, was transferred to Athens, where Athena and her priests could better protect it on the Acropolis in the event of a sudden Persian foray into the Aegean.

Although Athenian naval power was useful to suppress piracy and protect the city’s supplies, the main objective was political and military mastery of the Aegean world. At its height Athens ruled directly 179 states, which included perhaps 2 million Greeks; the most remote of these states were only an eight-day voyage—200 to 250 miles—from Athens. But Athenian naval power could be projected over the Mediterranean from Sicily to Egypt and the Black Sea; thus the world that had to consider Athenian policy seriously embraced perhaps 20 million people.

The most evident burden on the empire itself was the required payment of tribute to Athens. By 431 B.C. the voluntary contributions set half a century earlier had become forced payments. These funds helped pay the heavy costs of maintaining a fleet that was at sea a great part of every year to keep the empire under control.

Unlike the Roman Republic, which required from its Italian “allies” not cash but men for the Roman wars, the Athenian empire does not appear as a rule to have levied contingents of subjects for its galleys. But many allies were tempted by pay to serve as mercenaries alongside the poorer Athenian citizens drafted for the rowers’ benches. Athens could never have manned its large fleets in the Peloponnesian War out of its own citizen body.

By various decrees the Athenians limited the independence of their subjects, a direct violation of the basic principle of Greek political life, autonomia, the right of a state to use its own laws. Stripped to its essence, the Athenian Empire produced slavery (douleia and in the Peloponnesian War the Spartans were able to raise the battle cry of liberation from that enslavement by an Athenian elite. The true judgment of the subjects is evident in the fact that whenever they saw a chance to escape from Athenian naval domination, they revolted, and in 404 B.C. they helped to topple the Athenian Empire.

In 431 B.C. Athens with its empire and Sparta with its allies came to open war, the famous Peloponnesian War immortalized by Thucydides. For modern students of sea power, this protracted conflict provides guidance as valuable as the vicissitudes of British naval history from the seventeenth to the twentieth century. The first phase of the war, from 431 B.C. to 421 B.C., was a contest between the elephant and the whale. The Peloponnesian league had only limited naval strength and not enough funds to build a large navy or hire the necessary rowers. Although its powerful army laid Attica waste, it could not attack Athens proper, which was safe behind its stone walls and drew much of its food from overseas; nor were the Spartans able to keep their army active throughout the agricultural season. Sparta stood for liberty, but it could not help Athenian subjects overseas to secure their freedom. When Mytilene rebelled in 428—427, the Athenian fleet inexorably reduced it once more to obedience.

Yet Athens could not force Sparta to surrender, for it dared not meet the invincible Spartan hoplites by land. Pericles, the political leader of Athens, had laid down the fundamental lines along which Athens would fight. When the enemy invaded Attica, its citizenry abandoned their ancestral homes and poured into the city for refuge, remaining there until the Spartans retreated. Although they raged against Pericles and even temporarily removed him from office, he adhered to his policy of wearing down the enemy by naval raids about the Peloponnese. Above all, Athens must keep intact its fleet, on which rested its imperial revenues and its overseas supplies of grain. This cautious approach, similar to England’s naval strategy during the Napoleonic Wars, could not bring victory, but it could avoid defeat.

Down to 421 B.C. the Athenians had the better of the widely scattered actions. Sparta itself they could not touch, but at points about the Peloponnese they set up coastal forts to which disaffected Helots (people of Sparta’s lowest class) and others might escape. By a chance of war the Athenian fleet cut off a whole battalion of Spartans on an island at Pylos and forced them to surrender. Among the prisoners were 120 Spartan “Equals”—a sizable part of Sparta’s citizen body—and the Spartans thereafter dared not invade Attica lest these hostages be executed.

The last major actions in the first phase of the war took place along the coast of Macedonia, where a brilliant Spartan leader, Brasidas, was able to get at Athenian subject states by land and incite them to rebel. In a battle at Amphipolis in 422 B.C., both he and the radical Athenian leader Cleon were killed. The two sides were ready to call a halt to the inconclusive struggle, and the Spartans acquiesced in a peace treaty that led to massive discontent and defection of their allies, whose grounds of complaint against Athens were almost ignored in the treaty.

Athens had done as well as could have been expected, and perhaps better. The Aegean empire was intact; in western waters its power had risen; the Peloponnesian league had been sorely shaken. Throughout history a naval power has usually been able to defeat a land power only if it secures a powerful land ally; but no major Greek state had been willing to link itself to Athenian imperialism.

Yet, since their eager expansionism had been essentially checked, the Athenians were far from satisfied. Under the strains of war, the temperament of the assembly had become harsher, especially after Pericles died in 429 B.C., a victim of an epidemic akin to typhus. The epidemic and overcrowding affected everyone; the devastation of the countryside and the losses of the army in several land battles damaged especially the rural classes. Now that the war was over, Athenian opinion was divided, and so was Athenian leadership. Nicias, a conservative aristocrat, was a second Pericles, save that his religious piety and sense of duty were not matched by firmness and clarity of thought. Far more radical was the handsome and popular Alcibiades; a pupil of Socrates, he eventually persuaded his fellow citizens to intervene in the affairs of far-off Sicily.

During the war the Athenians had made diplomatic and naval gestures toward unseating Syracuse, the main power in the island; now an appeal from the native state of Segesta promised wider local support. Nicias stood in opposition and pointed out the basic strategic requirement that Athens remain powerful in the Aegean, but Alcibiades successfully rallied a spirit of excitement, heightened by possible economic profits. The assembly not only voted to send an expedition but also set its size on the large scale that Nicias had proclaimed necessary; and it placed in command a triumvirate consisting of Nicias, Lamachus (a professional general), and Alcibiades. That in itself was almost enough to ensure disaster for the greatest amphibious operation ever launched in Greek history. Nevertheless, the fleet of some 100 triremes and troopships rowed out of the harbor of Piraeus in gala array (June 415 B.C.), met another contingent off Corcyra (present-day Corfu), and set a westward course for Sicily.

The main Syracusan leader, Hermocrates, tried in vain to persuade his fellow citizens to meet the Athenians at sea; but the Athenian leaders gave the Syracusans time to prepare by land as they fell to wrangling among themselves about the proper course of action. Alcibiades was soon recalled by his enemies in Athens on grounds that he had profaned the sacred Eleusinian mysteries during a drunken revel. Rather than return to face probable death, he fled to Sparta, where he urged the Spartans to aid Syracuse and resume the war against Athens. Though Sparta sent only the general Cylippus to command the Corinthian relief expedition to Syracuse, he invigorated the Syracusans to withstand a great siege by the Athenian force.

Lodged in a swampy corner of the great harbor of Syracuse, Nicias grew more and more despondent and called for help, which was provided by a further expedition in 413 B.C. When the Athenians still failed to carry the city, their commanders decided to retreat by sea; but since an eclipse of the moon had just occurred, Nicias refused to leave for 27 days. During that period the Syracusans strengthened their ships and in a hand-to-hand naval battle in the great harbor defeated the Athenian forces. When finally Nicias led off his dejected army by land, it was cut to pieces by Syracusan cavalry. Nicias and the other Athenian leaders were executed, the Athenians died of hunger and thirst in the quarries where they were imprisoned, and the Athenian subjects were sold into slavery. All told, 50,000 men and over 200 triremes were lost in one of the most poorly conceived amphibious operations ever attempted.

That same year found Sparta again engaged in war with Athens. The Athenian Empire tottered amid widespread disaffection and even revolt among its subjects. Spartan fleets could cruise the Aegean almost at will, but the Athenians stubbornly held on.

In the earlier stages of the war, the Persian satraps of Asia Minor remained uncommitted, but from 411 on they came to Sparta’s aid by providing funds with which to seriously challenge Athenian hegemony. Spartan admirals, unfortunately, lost battle after battle, but finally the able commander Lysander took charge and on September l, 405 B.C., swooped down on the Athenian fleet at Aegospotami in the Hellespont and seized its ships while the crews were mostly on shore. He then swept down the Aegean, driving all the Athenian colonists ahead of him to Athens, which helplessly endured a siege by sea and land for several months before starvation forced surrender.

Sparta’s allies wished to see the tyrant city destroyed, but Sparta was content to tear down its Long Walls to the accompaniment of flute girls, restrict its navy to twelve ships, and install a temporary oligarchy—the Athenians were too wedded to democracy to support limited government for long.

The Athenian naval empire had failed, but not entirely through its own inherent weaknesses. True, the Athenians could never get a useful land ally, as the British were generally able to do in their wars with France, Spain, and Germany; they also treated their dependent states as subjects, while the Spartans presided over an alliance in which the allies had a real voice. Nonetheless, the fundamental cause of defeat was the ability of the Spartan political and military system to endure the stress of war and produce able commanders, whereas Athenian democracy proved unstable and was led ever more poorly by demagogues. The Spartans also discovered that victory depended on attaining naval mastery; they and, later, the Romans are almost unique in all history in facing the need to gain naval power and actually securing it.

Yet Western civilization owes much to the first great naval empire. Athens had become a democracy before it acquired Aegean mastery, but the self-confidence of its citizens strengthened popular support for a system of government that survived all disasters down to the time of Alexander. On the Acropolis rose the Parthenon, the most nearly perfect and expensive Doric temple ever built, thanks to imperial revenues. Down below, on the slopes of the sacred hills, audiences in the theater of Dionysius attended the first great Athenian tragedies and comedies. The study of history as a formal discipline also came into existence at this time, and the Athenian gadfly Socrates established philosophy as the pursuit of human wisdom. Not all of these advances, true, were the direct result of empire, but it was within this framework that Athenian citizens made Athens a lasting symbol of cultural greatness. MHQ


This article originally appeared in the Winter 1989 issue (Vol. 1, No. 2) of MHQ—The Quarterly Journal of Military History with the headline: The Athenian Century


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