Battle of Thermopylae Timeline

(August 480 BC (August 18–20, approximately))

The Battle of Thermopylae was fought in August 480 BC between an alliance of Greek city-states, led by King Leonidas I of Sparta, and the invading Persian Empire under King Xerxes I. Lasting three days, the battle is famous for the heroic last stand of the Greek forces, particularly the 300 Spartans, who held the narrow coastal pass at Thermopylae against vastly superior numbers before being outflanked and defeated. More Less

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Persian Expansion

Cyrus the Great founds the Persian Empire

550 BC

Cyrus the Great overthrew the Median Empire and established the Achaemenid Persian Empire, creating a vast imperial power that would expand across the Near East and eventually come into conflict with the Greek city-states.

Image source: Cyrus the Great

Darius I becomes King of Persia

522 BC

Darius I seized the Persian throne and consolidated the empire's power, reorganizing its provinces and armies, setting the stage for his campaigns against Greece and the eventual Greco-Persian Wars.

Image source: Darius the Great

First Persian invasion of Greece

492 BC

Darius I launched an expedition under Mardonius to subdue Thrace and Macedonia as a prelude to punishing Athens and Eretria for supporting the Ionian Revolt, though the fleet was wrecked near Mount Athos.

Image source: First Persian invasion of Greece

Xerxes I ascends the Persian throne

486 BC

Upon Darius I's death, his son Xerxes I inherited the empire and the unfinished project of avenging Marathon, spending years assembling one of the largest invasion forces ever gathered to conquer Greece.

Image source: Xerxes I

Xerxes crosses the Hellespont into Europe

Apr 480 BC

Xerxes' army crossed into Europe over engineered pontoon bridges spanning the Hellespont, beginning the massive march through Thrace and Macedonia toward northern Greece with hundreds of thousands of troops.

Image source: Xerxes's pontoon bridges

Persians sack and burn Athens

Sep 480 BC

With the pass breached, Xerxes' army advanced unopposed into Attica. Most Athenians evacuated to nearby islands and the Peloponnese, and the Persians captured and burned the largely abandoned city, including the Acropolis temples.

Image source: Greco-Persian Wars

Greek Resistance

Ionian Revolt begins in Greek Asia Minor

499 BC

Greek city-states in Ionia, aided by Athens and Eretria, revolted against Persian rule. The revolt's burning of Sardis provoked Darius I to seek revenge against mainland Greece, leading directly to the Persian invasions.

Image source: Ionian Revolt

Battle of Marathon

Sep 490 BC

A heavily outnumbered Athenian army under Miltiades decisively defeated a Persian landing force on the plain of Marathon, halting the first full-scale Persian invasion of Greece and boosting Greek confidence.

Image source: Battle of Marathon

Themistocles persuades Athens to build a fleet

483 BC

Athenian statesman Themistocles convinced his fellow citizens to use revenue from newly discovered silver mines at Laurion to construct two hundred warships, creating the navy that would prove decisive at Salamis.

Image source: Themistocles

Hellenic League formed by Greek city-states

481 BC

Facing word of Xerxes' massive invasion preparations, representatives of around thirty Greek states met and formed a defensive alliance led by Sparta, coordinating land and naval strategies against Persia.

Image source: Second Persian invasion of Greece

Battle of Salamis

Sep 480 BC

Themistocles lured the Persian fleet into the narrow straits of Salamis, where the more maneuverable Greek triremes inflicted a crushing defeat, destroying Persian hopes of naval supremacy and prompting Xerxes to return home.

Image source: Battle of Salamis

Battle of Plataea ends the Persian invasion

479 BC

A large allied Greek army under Spartan regent Pausanias decisively defeated Mardonius' Persian forces in Boeotia, ending Xerxes' invasion of mainland Greece and securing Greek independence.

Image source: Battle of Plataea

The Battle of Thermopylae

Simultaneous Battle of Artemisium

Aug 480 BC - Aug 20, 480 BC

Over three days, the allied Greek fleet fought the Persian navy off Cape Artemisium in storms and skirmishes. Upon news of Thermopylae's fall, the Greeks withdrew southward to protect Attica.

Image source: Battle of Artemisium

Persians assault the Middle Gate at Thermopylae

Aug 480 BC - Aug 19, 480 BC

For two days, Xerxes sent waves of Medes, Cissians, and his elite Immortals against the Greek phalanx in the narrow pass. The Greeks' superior armor, longer spears, and disciplined fighting repelled every assault with heavy Persian losses.

Image source: Battle of Thermopylae

Greek forces occupy the pass of Thermopylae

Aug 480 BC

King Leonidas I of Sparta led a force of about 7,000 Greeks, including 300 Spartans and their helots, to block the narrow coastal pass of Thermopylae, chosen for terrain that neutralized Persian numerical superiority.

Ephialtes betrays the Greeks with the Anopaea path

Aug 19, 480 BC

The local Greek Ephialtes revealed to Xerxes a hidden mountain track over Mount Kallidromos that bypassed the pass, allowing a Persian force under Hydarnes to flank the defenders and seal their fate.

Leonidas dismisses most allies; Thespians stay

Aug 20, 480 BC

Learning the flanking force was en route, Leonidas released most of the Greek contingents, retaining the 300 Spartans, around 700 Thespians who refused to leave, roughly 400 Thebans, and other loyalists to fight a delaying action.

Final stand and death of Leonidas

Aug 20, 480 BC

The remaining Greeks fought ferociously beyond the wall to the widest part of the pass, killing many Persians before being surrounded. Leonidas fell in battle, and the last defenders died under arrows after retreating to a small hill.

Image source: Leonidas I

Aftermath and Legacy

Simonides composes epitaph for the fallen at Thermopylae

470 BC

The poet Simonides of Ceos composed the famous epitaph honoring the Spartan dead: 'Go, tell the Spartans, stranger passing by, that here obedient to their laws we lie,' immortalizing the sacrifice of the Three Hundred.

Image source: Go Tell the Spartans

Herodotus records the battle in his Histories

440 BC

Writing decades after the war, Herodotus preserved the detailed account of the Battle of Thermopylae in Book VII of his Histories, which remains the primary ancient source and shaped the battle's enduring legend.

Image source: Histories (Herodotus)

Battle of Cnidus ends Spartan naval dominance

394 BC

A Persian-backed fleet destroyed Spartan sea power, illustrating how the Greek states that united against Xerxes later turned on each other while Persia regained influence in the Aegean.

Image source: Battle of Cnidus

Key Facts

The battle took place in August 480 BC during the second Persian invasion of Greece, led by King Xerxes I.
King Leonidas I of Sparta commanded the Greek forces, which included his famous contingent of 300 Spartan warriors along with several thousand allied troops from other city-states.
The Greeks held off the much larger Persian army for three days by defending the narrow pass of Thermopylae, neutralizing Persia's numerical advantage.
A local Greek named Ephialtes betrayed the defenders by revealing a mountain path that allowed the Persians to outflank them from behind.
Although the battle ended in a Persian victory, it became a symbol of courage and sacrifice and bought valuable time for Greece to organize its defense, contributing to eventual Greek victories at Salamis and Plataea.

Source

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