The Ionian Revolt (499-493 BC) was a major uprising of the Greek cities of Asia Minor against Persian rule, and is said to have either delayed an inevitable Persian invasion of mainland Greece, or made that invasion more likely (Greco-Persian Wars).
The Greek cities of Ionian and Aeolia on the coast of Asia Minor had fallen into Persian hands in the aftermath of the Persian Conquest of Lydia (547-6 BC). The Persians first crossed into Europe in around 513 BC when Darius launched a fairly unsuccessful campaign against the Scythian nomads north of the Danube. This was followed by the conquest of parts of Thrace in 512-5122, giving the Persians a foothold in Europe, and threatening the Greek grain trade routes into the Black Sea. The obvious next target for Persian attack were the cities of mainland Greece, but the Ionian Revolt came first, and gave the Persians a convincing reason for their invasion.
Our only major literary source for the revolt is Herodotus, and his account doesn't allow us to be entirely sure about the dates of events within the revolt. Here we will follow the timeline used by the Second Edition of the Cambridge Ancient History.
According to Herodotus one of the causes of the revolt was the plotting of Histiaeus, deposed Tyrant of Miletus. He was living in forced exile at the Persian court at Susa, while his son-in-law Aristagoras ruled Miletus. Histiaeus wrote to his successor encouraging him to revolt. Once the revolt had broken out he then convinced Darius that he could put it down, and was allowed to return home. He failed to convince the satrap Artaphernes and was forced to flee once again, ending his life as a pirate. He was captured and executed by Artaphernes after the end of the revolt.
The immediate trigger of the revolt was the failure of an attack on Naxos. A group of exiles convinced Aristagoras to support their attempt to regain power on Naxos. He won the support of Artaphernes, satrap of Lydia, who won over Darius I. A fleet of 200 triremes was gathered from the eastern Greek cities, and the expedition set off in 399. The Naxians were warned of the upcoming attack, managed to resist a four-month long siege. Eventually the Ionians and their Persian supporters were forced to abandon the siege.
In the aftermath of this failure Aristogoras decided to trigger a revolt against Persian authority. He began by summoning a council at Miletus, which decided in favour of war. He then sent messengers to the Ionian fleet, which was still concentrated after the expedition. A number of other tyrants were present with the fleet, and they were captured and deposed. Aristogoras himself gave up his tyranny, although in practise he remained in command. He asked each of the rebel cities to provide a general for their own forces, and then in the winter of 499 he left for mainland Greece, where he hoped to find allies.
Aristogoras had limited success in Greece. Sparta refused to help. Athens and Eretria were won over, but the Athenians only provided twenty ships and Eretria five. This small naval squadron arrived at Miletus in the spring of 498.
498 saw the only major Ionian land offensive of the war. A force largely made up of troops from Ephesus attacked Sardis and inflicted an embarrassing defeat on the Persians. However the Persians reacted quickly and the Greeks were caught during their retreat and defeated near Ephesus. The Ionian army was disbanded, and in the future the rebels limited themselves to operations near the coast. This defeat also caused the Athenians to withdraw their support and they resisted all further calls for help.
In the aftermath of the attack on Sardis the revolt spread to Cyprus, which had become part of the Persian Empire soon after Darius I came to the throne, to the Greek cities of the Bosporus and the Hellespont and to Caria. At about the same time Athens withdrew its support for the revolt.
On Cyprus the revolt was led by Onesilus, king of Salamis. He was the younger brother of King Gorgus of Salamis, and made repeated efforts to get him to revolt against Persia. Gorgus refused to take the risk, until in the aftermath of the outbreak of the Ionian Revolt Onesilus expelled him from the city and forced him into exile. Onesilus took the throne, and triggered a revolt against Persian authority.
On Cyprus only Amathus remained out of the revolt. Onesilus besieged Amathus (498-497), and called for help from Ionian. The Ionains responded by sending a fleet. At the same time Darius raised a Phoenician fleet and sent it, and a Persian army, to retake the island. The key campaign probably came in the summer of 497. The Persians marched across the island to Salamis, where a double land-and-sea battle was fought. At sea the Ionians defeated the Phoenicians, winning themselves control of the seas for a few years. On land the Cyprians began well, but were let down by treachery in their ranks, and eventually suffered a heavy defeat. Onesilus was killed in the battle and his brother restored to power. The other rebel cities were besieged and in most cases quickly surrendered. Soli held out for longest, but fell after a four month long siege. According the Herodotus the Cyprians lost their freedom after a year, so the sieges were probably all over by the end of 497. The siege of Paphos isn't directly mentioned by Herodotus, but extensive archaeological investigations have revealed many of the Persian siege works.
Back on the mainland the Persians made a major effort in 497. Darius sent three of his son-in-laws, Daurises, Hymaees and Otanes, to command the counterattack. Herodotus records an initial battle between this army and the force involved in the attack on Salamis, possibly a double-recording of the battle at Ephesus in 498. The Persian army then split into three, and conducted separate campaigns.
Daurises led his army to the Hellespont, where he recaptured five cities without facing much resistance. Hymaees operated a little further to the east, on the coast of the Propontis. Daurises was marching towards Parium when he learnt of the Carian revolt. He changed route and heading towards Caria to deal with the new threat. Hymaees moved west to replace him in the Hellespont area, where he recaptured the area around Illium, before dying of an illness. The third army, under Otanes and Artaphernes, was last to move, but then captured Clazomenae in Ionia and Cyme in Aeolis.
These successes unnerved Aristagoras, who decided to flee into exile in Thrace. After some initial success in the area he was killed while besieging a Thracian town, probably in 497 or 496.
Daurises met with mixed results in Caria. In 497 he won two major victories. He defeated a Carian force on the River Maeander. The Carians then received Milesian reinforcements and decided to fight on, but suffered a heavier defeat, possibly near their religious sanctuary at Labraunda. This was followed by a gap of uncertain length, in which the Carians regrouped and Daurises prepared to attack their cities. When he was finally ready to move he ran into an ambush at Pedasus, probably in 496 BC. Daurises and several other senior Persians were killed and his army was almost wiped out. This setback ended the first Persian counteroffensive, and the next major attack didn’t come until 494 BC.
Herodotus fills the gap with the exploits of Histiaeus, who reached Sardis, but was quickly forced to flee. He offered his service to the Ionians, but was rejected. He attempted to instigate a plot amongst the Persians at Sardis, but his efforts were discovered and his Persian contacts were killed. He attempted to force his way back into power at Miletus, but was repelled. He then fled to Mytilene, where he was given a small fleet of triremes, and began to operate as a pirate from a base at Byzantium.
The decisive battle of the war came in 494 BC. The Persians decided to concentrate all of their efforts against Miletus, sending a large army and a large fleet towards the city. The Ionians decided to leave the defence of the city itself to the Milesians, and to concentrate on the defeat of the Persian fleet. They gathered a fleet of 353 triremes from nine cities, and took up a position at the island of Lade. However when battle was joined the Ionian fleet collapsed (battle of Lade, 494 BC). The Samian fleet was first to desert, followed by the Lesbians, and then by several other contingents. Those that did stand and fight were defeated.
This left Miletus exposed to a siege, and the city fell after the walls were sapped. The men were killed or deported, the women and children sold into slavery and the temples destroyed. A destruction layer from this period has been discovered, confirming the destruction.
The Ionians now found themselves under attack from two sides. On one side were the Persians, who began a brutal reconquest of Ionia. On the other side was Histiaeus, who returned from Byzantium, invaded the island of Chios, which had been greatly weakened by the losses suffered at Lade. He then attacked Thasos, but abandoned this when the Persian fleet began to move towards him. He retreated to Lesbos, but soon ran short of food. He decided to launch a raid on the mainland, hoping to find food in Mysia, on the south coast of the Sea of Marmara. During this raid he ran into a Persian army commanded by a general called Harpagus and was defeated in battle at Malene (494 BC). He was captured at the end of the battle and was executed by Artaphernes, who didn't want to risk letting him near Darius.
The Persians began their campaign by restoring Aeaces as tyrant of Samos, and as promised Samos was left intact. They then occupied Caria. This took them the rest of the campaigning season, and they spent the winter at Miletus.
The campaign resumed in the spring of 493. First they captured the islands of Chios, Lesbos and Tenedos, and hunted down the entire population of the islands. A number of Ionian communities on the mainland were also taken. Their temples were destroyed and the better looking children were taken either as eunuchs or slaves.
Next the Persian fleet sailed around the coast into the Hellespont. The south coast had already been retaken during the failed three pronged campaign of 497-496. In 493 they conquered the areas north of the Hellespont, including the Chersonese. Miltiades, who would later command the Athenian army at Marathon, who was then the ruler of that area, was forced to flee into exile.
This ended the repressive period of the Persian campaign. They now began a more conciliatory period. In 493 Artaphernes summoned representatives from each of the Ionian states to Sardis and ordered them to set up a system of arbitration. He also measured each state's land area and set new levels of tribute that more accurately reflected their size.
In 492 the Persians made another major change in policy. Darius appointed his son-in-law Mardonius as the commander in Asia Minor. According to Herodotus he had been sent to punish Athens and Eretria for supporting the rebels, but as he sailed passed Asia Minor he replaced the tyrants who had been restored after the failure of the revolt with new democratic regimes. This plan was successful enough to allow Xerxes to recruit troops in Ionian for his invasion of Greece in 480.
Mardonius then went on to subdue parts of Thrace and gain the submission of Macedonia, but his fleet was destroyed by a storm while passing Mt Athos, and he was forced to abandon his plans for an attack on Athens. The Persians returned again in 490, this time attacking across the Aegean, but only to be defeated at the battle of Marathon (490 BC).