Greco-Persian Wars: Why did the Persian kings wage war against the Greeks?

The Persian Empire, also known as the Achaemenid Empire, is often described by historians as an empire that served as a model for many of the land-based empires in world history. Founded by Cyrus the Great in the mid-6th century BC, the Empire covered an enormous area.

The empire stretched from the eastern Mediterranean in the west to the Indus River Valley in the east. As a result, the Persian kings had dominion over diverse groups of peoples and cultures, including in places like modern-day Iran, Iraq, parts of Turkey, Egypt, Lebanon, Jordan, and Israel.

Beginning around the early 5th century BC, the Persian Empire set its sight on mainland Greece and mounted several campaigns against the region. Despite the hard-fought efforts of Persian rulers like Xerxes the Great and Darius the Great, the Persian forces were unable to fully conquer mainland Greece during what came to be known as the Greco-Persian Wars (499-449 BC). Persian invasions, including the famous battles of Marathon (490 BC), Thermopylae (480 BC), and Salamis (480 BC), were repelled by the Greek city-states who were primarily led by Athenians and Spartans.

In the article below, World History Edu explores the reasons why the Persian Empire waged war against the Greeks:

Read More: Notable Accomplishments of Cyrus the Great of Persia

Major Causes of the Greco-Persian Wars

For about five decades (i.e. from 499 BC to 449 BC), the Greeks fought tooth and nail to halt Persian expansion westward. Image: Greek hoplite and Persian warrior depicted fighting, 5th century BC.

For about half a century (i.e. from 499 BC to 449 BC), the Greeks fought tooth and nail to halt Persian expansion westward. The question that begs to be answered is: Excluding the desire for more territories, why did the Persian kings wage war against the Greeks?

Below, we take a deep dive into some of the key factors that contributed to the Persian Wars:

Persia’s use of tyrants to exert more control in its territories in Asia Minor

The Persian kings, including Cyrus the Great, were known for their policy of religious and cultural tolerance. They allowed conquered peoples to retain their own customs, languages, and religions. This approach contributed to the stability of the empire and helped to ensure cooperation and loyalty from diverse populations.

However, when it came to the inhabitants of the region of Ionia (what is today’s south of Izmir, Turkey), the Persian rulers found it very difficult to rule them. To exert their control over the Ionians, the Persian rulers appointed cruel tyrants to rule on their behalf.

Miletus was an ancient Greek city on the western coast of Anatolia. It was located in today’s Aydın Province, Turkey

One such tyrant was Aristagoras of the Ionian city of Miletus. The Greek city-state of Miletus, which was conquered by the Persians in the late 6th-century BC, were given the chance to self-rule provided they paid their taxes to their Persian overlords.

However, it so happened that it was not just the inhabitants of Ionia that loathed the Persian kings; the tyrants of those Greek city-states in Anatolia had deep hatred for the Persian kings due to the yearly taxes they had to make to the empire. The Ionians dreamed of one day rising up against the Persia’s rule.

The failed Siege of Naxos in 499 BC by a joint expedition of Ionian and Persian forces

Best known as the largest island of the Cyclades in the Aegean Sea, the city of Naxos was a prosperous and influential island city-state. In 499, a number of exiled Naxian noblemen and affluent people sought the help of the tyrant Aristagoras in their quest to return to their island.

Aristagoras was advised by his counselors to take up the offer as it would boost his standing and influence in the region. Therefore, Miletus offered to help those exiled Naxian aristocrats return to power in Naxos. With the approval from his Persian overlord, King Darius I (also known as Darius the Great), Miletus embarked upon a military campaign against Naxos.

The Milesian-Persian expedition to Naxos was led by Miletus and Artaphernes, the brother of Darius and governor of a local satrap. Persia also supported Miletus planned siege of Naxos with a force of 200 triremes, who were led by Persian general Megabates.

Naxos is the largest Greek island in the Cyclades in the Aegean Sea

Due to a number of factors, including a lack of proper coordination between Aristagoras’ forces and the Persians, the Siege of Naxos ended up being a huge fiasco. Apparently the Naxians had received a tip-off on the impending Milesian-Persian invasion. It is unclear who exactly gave the information to Naxians, but the generally accepted view is that the hint came from Megabates himself. It’s believed that the Persian general sought the downfall of Aristagoras after the two men had a big argument. In any case, the Naxians, after receiving that vital piece of intelligence, proceeded to bolster their defenses and braced themselves for a long siege.

The Naxians managed to hold out for four months against Aristagoras and his forces. Realizing that they were making no significant progress, a frustrated Aristagoras decided to lift the siege and return to Miletus. Not only did he feel beaten down by the failed siege, the Ionian general had also sunk in a lot of money into the siege.

Generally speaking, the tyrants that ruled the Greek city-states of Ionia were nominated by the Persian satrap in Sardis. Image: Artaphernes – an Achaemenid nobleman and the younger brother of Darius the Great

Sensing a possible backlash from not just his own people but from Darius, Aristagoras feared the worst. Therefore, he came up with plan that would distract Ionians and take attention away from his military debacle at Naxos. Aristagoras incited the people of Miletus to rebel against the Persian king. And in a few months, the rebellion spread to other Greek city states in western Anatolia, including Caria and the island of Cyprus. Lasting from 499 to 493 BC, the revolt came to be known as the Ionian Revolt.

Causes of the Greco-Persian Wars

Frustrated by the resistance and the lack of progress, the besieging force decided to abandon the siege of Naxos after four months. Aristagoras withdrew his Ionian forces without capturing Naxos, and the fleet returned to mainland Greece. The siege of Naxos was the first major military action of the Ionian Revolt.

Greek support for the Ionian Revolt against the Persian king

As Persia’s power and influence increased in the region, some city-states in mainland Greece began to get a bit nervous that the Persian king would set his sight on the mainland. Therefore, when the Ionian Revolt broke out in 499 BC, there were a number of mainland Greek city-states that saw it as an opportunity to weaken Persia’s hold in the region.

Powerful Greek city-states like Eretria and Athens offered to help the Ionians get rid of their Persian overlord. In 498 BC, a joint Greek force attacked and sacked Sardis, the famous and important city that served as the capital of Persian satrapy of Lydia. Sardis, which at the time was ruled by Artaphernes, the younger brother of Darius, could do very little to stop the Greek-Ionian invasion.

Cylinder seal of Darius the Great, ruler of the Achaemenid Empire

After successfully taking Sardis, the Greek-Ionian rebels journeyed home; however, they were caught unaware by Persian forces, who defeated them at the Battle of Ephesus. The defeat fractured the revolt and made Athens and Eretria withdraw their support for the Ionian Revolt.

Regardless, the Ionians stayed committed to their rebellion against Darius’ rule. As a result, the revolt continued to spread to other places in western Anatolia. The rebels even managed to push to Propontis and the Hellespont (known today as the Dardanelles or the strait of Gallipoli). Ionian rebels captured Byzantium and liberated a number of other cities nearby from Persians. The Ionian-Persian conflict would enter a stalemate for a couple years.

Persian satrapy of Lydia

The burning of Sardis had significant consequences for the Ionian Revolt and the ensuing Greco-Persian Wars. Image: Persian satrapy of Lydia

However, in 494 BC, Darius, having grown tired of the Ionian rebels, decided to nip the revolt for good. The Persian ruler marshalled a significant part of his forces and headed for Miletus, the Ionian city where the revolt began. With an outnumbering army and navy, the Persians crushed Miletus and its allies at the Battle of Lade in 494 BC. The defection by some generals of the Samian fleet tremendously weakened the fighting spirit of the Greeks, resulting in Persian victory.

According to Greek historian Herodotus, the main source of the Greco-Persian Wars was because the Persians wanted to exact a huge price on the people of Miletus as they were the ones who started the Ionian Revolt in the first place. The Greek historian states that Persians killed many of the city’s inhabitants, castrated the young men, and then sold the women and children into slavery. The damage inflicted on Miletus caused the city never to rise to its former glory again.

Seeking revenge for Miletus’ role in instigating the revolt against the Persian Empire, Persian king Darius the Great laid waste to Ionian city of Miletus. The few lucky inhabitants of the city that survived after the war were sold into slavery. Image: The ruins of Miletus

After Lade, many the revolting Ionian cities, including Caria, laid down their weapons and surrendered to the Persians. Having sent a message to the rest of Ionia through the destruction of Miletus, Darius made light work of islands such as Tenedos, Lesbos and Chios. One by one, Darius took back almost all of the Ionian cities.

And by 492 BC, almost all of Asia Minor was in firm control of the Persian ruler, and the Ionian Revolt had been successfully crushed by the Persians. Despite his re-subjugation of the Ionians, Darius was not through with the Greeks. The Persian king of kings desired nothing more than to punish the city-states of mainland Greece for their support of the Ionian Revolt. He set his eyes on Athens and Eretria, thus marking the beginning of the first Persian invasion of Greece (492-490 BC) which was aimed at conquering the whole of Greece.

Greek support for Ionian Revolt

The Ionian Revolt triggered the first phase of the Greco-Persian conflict. Persian king Darius the Great set out to bring Asia Minor into the Persian fold, and thus the first Persian invasion of Greece began in 492 BC.

Revenge for the burning of Sardis

As stated above, forces from Athens and Eretria joined Ionian rebels in the capture and razing to the ground of Sardis, the capital of the Persian province of Lydia. Even after re-subjugating all of Asia Minor to his control, Darius the Great was still pained by the destruction of Sardis by the Greeks.

Sardis was a significant and prosperous city, serving as an administrative and cultural center for the Persian Empire in Asia Minor. It was home to a large Persian garrison.

As part of the Ionian Revolt, the Greek city-states launched an attack on the Persian regional capital of Sardis, located in Lydia (western Asia Minor). The exact details of the assault and the Greek forces involved vary in different historical accounts. Image: The burning of Sardis by the Greeks and the Ionians during the Ionian Revolt in 498 BC.

The Greek forces, led by Aristagoras, managed to breach the defenses of Sardis and capture the city. The capture of such a prominent Persian stronghold was a significant victory for the Greek forces and bolstered their confidence.

However, after capturing the city, a fire broke out, either accidentally or intentionally, resulting in the burning of Sardis. The fire quickly spread and caused widespread destruction, including damage to the famous Temple of the goddess Cybele, an important religious site in the city.

Darius commanded his servant to remind him on a daily basis of his vow to exact the heaviest of punishment upon the cities of mainland Greece, especially the Athenians. The servant would whisper into Xerxes’ ear, “Sire, remember the Athenians.”

Not even the passing of Darius the Great in 486 BC could quench the Persians’ appetite for revenge. Darius’ successor, Xerxes I, ascended the throne holding an even greater desire to punish Athens and mainland Greece for their involvement in the Ionian Revolt. Darius obviously had witnessed just how pissed his father was about the destruction of Sardis and the so-called treachery by the Greeks. Therefore, he took up the cause.

Other causes of the Greco-Persian Wars

Greco-Persian Wars

The Greco-Persian Wars was a direct consequence of the Ionian Revolt which lasted from 499 BC to 493 BC.

It is important to note that the Persian Wars were not a single, continuous conflict but a series of conflicts that occurred over several decades. The two most famous Persian Wars are the Greco-Persian Wars, which included events such as the Battle of Marathon, the Battle of Thermopylae, and the Battle of Salamis. These wars had a profound impact on shaping the course of Western history and solidifying the cultural and political identity of ancient Greece.

Some other notable causes of the Greco-Persian Wars are:

Economic Interests – trade and shipping routes

The Greek city-states, especially Athens, were prospering and developing their trade networks, which threatened Persian economic interests in the region. Persian control over the Greek city-states would have given them control over important trade routes and resources.

Cultural and Political Differences between the Greeks and Persians

The Persian Empire and the Greek city-states had significant cultural and political differences. The Persians had a centralized autocratic system, while the Greeks valued their independent city-state governments and democratic practices.

Despite its so-called enlightened philosophies and democratic institutions, the Greeks still practiced slavery. On the other hand, slavery was almost unheard of in the Persian Empire.

These differences in governance and cultural values contributed to the conflicts between the two civilizations.

Notable facts about the Persian Empire, also known as the Achaemenid Empire

Ancient Persia

Founded by Cyrus the Great around 540 BC, the Persian Empire went on to conquer most of Mesopotamia, including the Babylonians, Anatolia, and some parts of North Africa. Image: Achaemenid Empire under different kings.

The Persian Empire, also known as the Achaemenid Empire, was one of the most significant and influential empires in ancient history.

Here are some key points about the Persian Empire:

  • The Persian Empire was founded by Cyrus the Great, who successfully united several Persian tribes and established the empire in the mid-6th century BC. Cyrus’s successors, particularly Darius I, expanded the empire to its greatest extent.
  • At its height, the Persian Empire covered an enormous area, stretching from the eastern Mediterranean in the west to the Indus River Valley in the east. It included modern-day Iran, Iraq, parts of Turkey, Egypt, Israel, Jordan, Lebanon, and several other regions.
  • The Persian Empire was known for its efficient administrative system. The empire was divided into provinces called satrapies, each governed by a satrap (governor) who reported to the central Persian authority. The empire implemented a system of roads, postal services, and a common currency, which facilitated communication and trade.
  • The Persian kings, including Cyrus the Great, were known for their policy of religious and cultural tolerance. They allowed conquered peoples to retain their own customs, languages, and religions. This approach contributed to the stability of the empire and helped to ensure cooperation and loyalty from diverse populations.
  • The Persians undertook impressive construction projects, including the building of grand palaces, cities, and infrastructure. The city of Persepolis, with its monumental structures and royal palaces, is one of the most famous examples of Persian architecture.
  • The Persian Empire faced challenges and eventually declined. It faced internal conflicts, rebellions, and invasions by outside forces, notably from Alexander the Great and his Macedonian army. By the 4th century BC, the Persian Empire was absorbed into the larger Hellenistic Seleucid Empire.

Historical accounts of the Greco-Persian Wars

Almost everything that we know about the 50-year Greco-Persian Wars comes from the 5th-century BC Greek historian and geographer Herodotus (c 484 – c. 425 BC). The account of the Persian Wars is found in Herodotus’ Historia (“the Histories”), which was written around 440-430 BC.

Herodotus – the famous Greek writer, historian and geographer – is credited with inventing the field of history; hence, his epithet “The Father of History”. Image: A Roman copy (2nd century AD) of a Greek bust of Herodotus from the first half of the 4th century BC

As a matter of fact, had it not been for the accounts provided by Herodotus, who is sometimes referred to as “The Father of History”, we would not have known much about the Persians. Herodotus was not the only Greek historian who wrote about the Persians. Athenian historian and military general Thucydides (c. 460 – c. 400 BC) had some bit of history about the Persians in his work History of the Peloponnesian War.

About five centuries after the passing of Herodotus and Thucydides, Roman historian and biographer Plutarch provided a more comprehensive account of the military history of Greece and their interactions with the Persians. Plutarch’s account was contained in the biographies (i.e. in Plutarch’s Lives of the Noble Greeks and Romans, also known as Parallel Lives) of key Athenian statesmen and generals such as Cimon, Aristides and Themistocles. Plutarch had the chance to write his work by drawing directly from a number of ancient sources that no longer exist today.

Greek historian Thucydides

Similar to Plutarch, first century BC Greek historian Diodorus Siculus provides an account of the Persian Wars in his famous work Bibliotheca historica. It’s believed that Sicilian historian drew directly from earlier works by Greek historians, especially 4th-century BC historian Ephorus.

Basically, the historical accounts about ancient Persia might be filled with some bias they were written by outsiders, i.e. Greek historians.

The Serpent Column located in Istanbul, Turkey

The Serpent Column, which is now located in Istanbul, Turkey, was built by the Greeks to commemorate their hard-fought win over the Persian Empire of Xerxes the Great at the Battle of Plataea in 479 BC. The ancient bronze column was originally located at Delphi (in today’s Phocis, Greece). During the reign of Roman Emperor Constantine the Great, the column was relocated to the Hippodrome of Constantinople in Constantinople (now Istanbul, Turkey).

Serpent Column

The Serpent Column was built by the Greeks to commemorate their hard-fought win over the Persian Empire of Xerxes the Great at the Battle of Plataea in 479 BC. It is located in today’s Istanbul, Turkey.



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