Darius had been interested in Greece for some years before the Ionian rebellion, and the desire to avenge the burning of Sardis had added an additional spur to his ambition. In 492 BC he sent his son-in-law Mardonius west at the head of a large force. Though Mardonius successfully restored Persian prestige in northern Greece, conquering Thrace, Thasos, and Macedonia, the fleet was wrecked off Mount Athos on the Chalcidic peninsula, and Mardonius was forced to turn back. Darius promptly began mobilizing for another expedition, one that would sail straight across the Aegean, avoiding the treacherous promontories of the north. Mindful of the fate of Miletus, many Greek cities yielded to the demand of Darius' heralds for earth and water, the proverbial tokens of submission that signaled recognition of the king's supremacy on land and sea. The islanders felt they had little choice, and on the mainland Argos and Thebes went over to the Persians. Sparta and Athens, however, remained steadfast in their opposition.

Darius' first order of business was to punish Athens and Eretria for their role in the Ionian rebellion. In fact, it may have been the primary purpose of his expedition. In the summer of 490 his fleet arrived in Greece, commanded by his nephew Artaphernes and Datis, a Mede. The figure given by Herodotus of six hundred ships is probably exaggerated, but Datis and Artaphernes may have had twenty thousand men with them, one of whom was the aging Hippias, the exiled ruler of Athens whom they hoped to reinstall as both Athenian tyrant and Persian vassal. En route the Persians burnt the town and temples of Naxos, deport ing their captives; elsewhere they pressed men into service and seized children as hostages. After a siege of less than a week, Eretria was betrayed from within. The Persians burnt the Eretrians' temples in revenge for those destroyed at Sardis and deported the population in accordance with Darius' orders. (Several centuries later the peripatetic prophet of the Roman empire Apollonius of Tyana reported finding the descendants of the deported Eretrians at Ardericca in Cissia, still speaking their native Greek.) From Eretria the Persians moved down on Marathon in the old Peisistratid stomping ground of northern Attica.

The Athenian assembly immediately voted to dispatch their forces to Marathon, and a runner, Pheidippides (or perhaps Philippides) was sent to Sparta, covering, so the story went, fully 140 miles by the next day. The Spartans, however, could not take advantage of the speed with which the message was delivered, for, they explained to the breathless Pheidippides, they were celebrating a festival of Apollo, the Carnea, and were forbidden to march until the full moon. As the Spartans were deeply religious and no cowards in war, their explanation may have been sincere.

Herodotus' figures concerning the Battle of Marathon are probably erroneous, but it is likely that the Athenians were outnumbered, if not as outrageously as he suggests then at least by a factor of two to one. The Persians had the more versatile force, with cavalry, archers, and skirmishing troops, but the Athenian force consisting essentially of hoplites was more heavily armed. The most serious problem faced by the Athenians was the lack of a commander, for all decisions lay with the ten strategoi (the board of executives created by Cleisthenes) deliberating as a body. As some wanted to wait for the Spartan reinforcements expected after the full moon and others thought delay risky, there was danger that a deadlock in the Athenian camp would throw the victory to the Persians and Greece would be overrun. When the Athenians learned that some of the Persian troops and cavalry were missing and suspected that part of the Persian forces were heading for Phaleron, it seemed to several generals that the moment to strike had come, even though the moon was full and the Spartans could be expected shortly; any delay could be fatal. The strategos Miltiades seems to have played a key role in saving Greece.

A nephew of the Miltiades whom Peisistratus had dispatched to protect Athenian interests in the Chersonese (thus conveniently disposing of a potential rival), Miltiades the younger had inherited his uncle's power and had spent much of his life in the remote outpost. In part because he was a member of the prominent Philaid clan and indeed a distant relative of Peisistratus himself, he became the victim of Athenian factional politics on his return to Athens in 493 BC when he was prosecuted for alleged tyranny in the Chersonese. Since it is impossible to see why the Athenians would worry about one of their own citizens tyrannizing abroad, Herodotus is surely right to ascribe the trial to the machinations of Miltiades' enemies (6.104); alternative rumors ascribed the attack to Themistocles or the Alcmaeonids. In any event, Miltiades was acquitted and went on to take the lead in the Greek victory over Darius, persuading the polemarch Callimachus and several of the other strategoi to let him direct Athenian strategy. Herodotus offers a stirring rendition of his speech:

Callimachus, it is up to you, right now, to enslave Athens or to make her free, and to leave for all future generations of humanity a memorial to yourself such as not even Harmodius and Aristogiton have left. Right now, Athens is in the most perilous moment of her history. Hippias has already shown her what she will suffer if she bows down to the Medes, but if this city survives, she can become the foremost city in all Greece. Now, I'll tell you just how this is possible, and how it is up to you--and only you--to determine the course of events. We ten generals are split right in two, with half saying fight and the other half not. If we don't fight now, I am afraid that a storm of civil strife will so shake the timber of the Athenian people that they will go over to the Medes. But if we fight now, before the cracks can show in some of the Athenians, and provided that the gods take no sides, why then we can survive this battle. All this depends on you. It hangs on your decision--now. If you vote with me, your fatherland will be free and your city will be first in all of Hellas, but if you choose the side of those who urge us not to fight, then the opposite of all the good I've spoken of will fall to you." ( The Histories 6.109; Blanco 1992)

And so, early one morning in late September of 490, under Miltiades' command, the Athenians, flanked by some Plataeans, ran down the hill on which they had encamped, covering the mile or so that divided them from the Persians at double speed despite the weight of their hoplite armor. Aristides and Themistocles commanded their tribal contingents in the center, while Canimachus commanded on the right wing and the Plataeans held the left. Knowing they were outnumbered, the Athenians packed their wings as tightly as they could, concentrating as many men as possible on the outer ends of their formation, even though it meant leaving the center thin. Despite their numerical superiority the Persians were unable to withstand the disciplined and determined hoplites fighting in defense of their freedom. (The Greeks also had better armor and longer spears.) In the flight to their ships, many of the Persians were bogged down in the marshes.

Arriving too late to participate in the fighting, the Spartans visited the battlefield and surveyed the Persian corpses. Herodotus maintained that the Athenians lost 192 men, the Persians 6400. The Greek statistic is probably correct, for the names were inscribed on the battlefield; they included Callimachus. The dead were cremated where they had fallen, and a monument was subsequently erected on the site. Some Plataeans and some Athenian slaves also died, but their numbers are unknown. The playwright Aeschylus himself fought at Marathon. The epitaph he composed for himself makes no mention of his stupendous achievements as a tragic dramatist but speaks only of his service in this battle for freedom: "The glorious grove of Marathon," he wrote, "can tell of his valor--as can the long--haired Persian, who well remembers it." Throughout the next decades, the Marathonomachoi--men who had fought at Marathon--enjoyed singular prestige in Athens and came as time went by to represent the simple virtues of the older generation in an increasingly luxurious and complex society. About a quarter century after the battle it was memorialized in a painting in the Stoa Poikilç (painted portico) at the north end of the Athenian agora; Callimachus, Miltiades, Datis, and Artaphernes could all be identified, as well as Aeschylus' brother Cynegirus hanging onto the Persian ship, to which he clung intrepidly until his arm was cut off by an axe. Gods and heroes were present at the battle as well--Heracles, Athena, and Theseus, who many believed had offered phantom aid on the battlefield as Homeric gods had done at Troy.

Not all Greeks rejoiced in the defeat of Persia. A shield signal was apparently flashed from Athens after the battle advising the Persians that the city was prepared to surrender. Any connection between the Alcmaeonids and the signal was indignantly denied by Herodotus, who tended to favor the Alcmaeonids and seems to have used Alcmaeonid sources in his writing, but just such a connection was common gossip at the time. In any event, someone at Athens wished the Persians well. Over the years, accusations of Persian sympathies would dog aspiring Athenian politicians and offer an easy route to damaging a controversial figure's reputation.

Athenians held their leaders to high standards. Although the history of the fifth and fourth centuries would provide numerous examples of the exacting temperament of the demos, the earliest are among the most interesting. Shortly after the battle of Marathon, Miltiades was impeached in the assembly and condemned to pay a stiff fine. He died in disgrace before he could pay, and his son Cimon discharged the debt. The circumstances were curious. Because of his heroic standing after the victory of Marathon, the Athenians were agreeable to granting Miltiades ships on his promise that he would make them rich. When his attack on the island of Paros ended in failure and embarrassment--Herodotus claims the wound that eventually killed him was sustained while violating the sanctuary of Demeter--he was impeached at Athens and had to attend his trial on a stretcher, as his wound was beginning to gangrene. The Athenians considered putting him to death. Although it is impossible to know just how much the voters in the assembly had known about the object of Miltiades' expedition--security considerations would have argued against openly naming Paros, which had sided with the Persians during the war--what is clear is that the demos had developed the confidence to hold its leaders accountable. Throughout the decades that followed, interaction between the demos and its leaders would be characterized by a changing dynamic that helped define the nature of the democracy as it unfolded.

It was not only in Athens that political leaders tended to come to bad ends. Spartan kings had a habit of getting into difficulties as well. After winning a decisive victory over Sparta's inveterate enemy Argos at Sepeia, Cleomenes was accused by the Spartans of sparing the city as a consequence of bribes. A couple of years later, when he had enlisted the Delphic oracle in machinations to engineer the deposition of his fellow king Demaratus, further accusations of bribery followed. Cleomenes fled to Arcadia, where he stirred up the inhabitants against Sparta. Though the Spartans chose to pardon and recall him, he apparently lost his mind. If Herodotus' sources are correct, he perished horribly while displaying the Spartans' proverbial endurance of physical pain. When he came home, Herodotus maintains,

he was immediately seized by some frenzy of madness (even earlier he had been somewhat disturbed in his mind). When he met any of the Spartiates, he would strike at them in the face with his stick. For so doing, and because of his distraction, his relatives confined him in a pillory. But being so a prisoner., as soon as he saw his guard alone from the rest, he asked him for a knife. At first the guard refused to give him one, but the king kept threatening him with what he would do to him afterwards, until the guard, who was just one of the helots, finally gave him a knife. Cleomenes took the knife and started mutilating himself from the shins up. He cut the flesh lengthwise and went up from shins to thighs and from the thighs to the hip and the flanks, until he got to the belly. And he made mincemeat of the belly too and so died. ( The History 6.75; Grene1987)

The exiled Demaratus fared better. As some of his conflict with Cleomenes had been over his sympathy with the pro-Persian party at Aegina, he found a warm welcome in Persia, served as an adviser in the wars with Greece, and was rewarded for his services with the grant of four cities in Asia Minor.

The nature of political leadership in Athens changed shortly after the Battle of Marathon in a very specific manner. Events surrounding the campaign had impressed on the Athenians the importance of sound military leadership. Shortly afterward they signaled this awareness by a change in the method of selecting archons, who as primarily judicial officials had come to seem less important in comparison with the strategoi, who had life-anddeath military responsibilities. In 487 they began choosing archons by lot from a large pool (perhaps a hundred men in total?) contributed by the various demes--the method already used for selecting members of the Council of Five Hundred. This shift ensured that men of ambition would stand not for the archonship, a nonrenewable office, but for the strateçgia (generalship). It also served gradually to undermine the status of the venerable Council of the Areopagus. Because it was composed of former archons, as time went by it came more and more to be filled by men who had been chosen by lot. It seems likely that the originator of this move was the feisty Themistocles. Not only was Themistocles hostile to the aristocratic ethos that granted special power and prestige to the Areopagites; as a man who had already served his archonship and was eligible to repeat only his generalship, he had a more immediate interest in enhancing the role of the strategoi at the archons' expense. Selection by lot was a procedure commonly associated with democracy in Greece. It worked to discourage the machinations of special interest groups and ensure that a significant proportion of the men eligible for each office would participate in politics, and it seemed to offer the gods a role in choosing officials. The Athenians were no fools, however. They subjected all would-be officeholders to an interrogation known as dokimasia, and they declined to employ the lot to select commanders for the state's armed forces. As a consequence, the generalship became the most prestigious office in the government, and the ten strategoi outranked all other Athenians in authority.

At the same time, the Athenians began deploying an unusual procedure for preventing any one individual from taking over the state, although the rapid disappearance of several of Themistocles' opponents serves as a reminder that the method was not foolproof. One of the innovations sometimes attributed to the reformer Cleisthenes was ostracism, a system whereby every spring the Athenians had the option of voting to send one of their fellow citizens into exile for ten years. The peculiar process took its name from the broken pieces of pottery known as ostraka on which the voters inscribed the name of the man they wanted to banish. No accusation was lodged; no shame attached to the departure; the exile's citizen rights and material possessions would be waiting for him upon his return. But the man who was identified as dangerous by receiving the most votes would be compelled to withdraw from Attica for a ten-year cooling-off period. Inevitably historians have wondered why, if this procedure was really developed by Cleisthenes, the first man to be exiled in this fashion--a Peisistratid named Hipparchus--was not ostracized until 487, fully twenty years after Cleisthenes' ascendancy. The answer may lie in the minimum of six thousand votes that the Athenians demanded be cast; perhaps the ostracism of Hipparchus was not the first attempted ostracism but just the first one in which the quorum was met, the first that "took." Perhaps, however, ostracism was simply invented later. It is probably no coincidence that the first man known to be ostracized bore such an unfortunate name; one common explanation of ostracism was that it was designed to ward off tyranny. Whenever ostracism was first devised, it should perhaps be seen as a means of replacing the expulsion of whole family groups, like the Alcmaeonids, with the less sweeping exile of a feared individual. Several prominent men were ostracized in the 480s--Megacles, leader of the Alcmaeonids, in 486; Xanthippus, the father of Pericles, in 484; and Themistocles' great rival Aristides, in 482.

What role Themistocles played in the first three ostracisms is a matter of speculation, but his conflict with Aristides is indisputable, and the ostracism of 482 compelled the Athenians to choose between two distinct policies. Civil war might be averted by the safety valve of ostracism, but the danger of another contest with Persia also had to be addressed. Darius raised taxes in the summer of 486, thus arousing suspicion that he was gathering resources to finance a new invasion of Greece. He would probably have some support in northern Greece--Thessaly, for example--and no doubt in the south as well. By this time the Persians were well aware how divided Greek cities were among themselves--they knew of the rivalry of Argos with Sparta, Aegina with Athens--and how racked by internal conflict. In the event, Thessaly, Locris, and all of Boeotia except Plataea and Thespiae would in fact give the requisite earth and water to the Persians after they learned Persian forces had crossed the Hellespont. Darius' project had to be delayed, however, because of a rebellion in Egypt sparked by the increase in taxes. In the fall of 486 BC he fell ill and died.