The Greek defense at Thermopylae delayed the Persian invasion long enough to enable the naval victory at Salamis and ultimately the defeat of Xerxes.
Key Facts
- Date
- 480 BC (July–September)
- Duration of battle
- Three days of direct combat
- Greek force size
- Approximately 7,000 men
- Spartan contingent
- 300 Spartans under Leonidas I
- Persian army estimate
- 120,000–300,000 soldiers (modern scholars)
- Greek rear-guard
- 300 Spartans, 700 Thespians held final stand
By the Numbers
Location
Cause → Event → Consequence
The second Persian invasion of Greece, led by Xerxes I, was a delayed response to the Persian defeat at the Battle of Marathon in 490 BC. By 480 BC Xerxes had assembled a massive land and naval force. Themistocles proposed blocking the Persian advance at the narrow pass of Thermopylae while simultaneously contesting the Persian fleet at the Straits of Artemisium.
A Greek allied force of roughly 7,000 men, including 300 Spartans commanded by King Leonidas I, held the narrow pass of Thermopylae against an overwhelming Persian army for seven days. After a local resident named Ephialtes revealed a flanking path, Leonidas dismissed most of the Greek army and remained with a small rear-guard—300 Spartans, 700 Thespians, and others—who fought to the last.
The fall of Thermopylae allowed the Persians to overrun Boeotia and sack the evacuated city of Athens. However, the Greek fleet subsequently defeated the Persian armada at Salamis, forcing Xerxes to withdraw most of his forces to Asia. The following year the Greeks decisively defeated the remaining Persian army under Mardonius at Plataea, ending the second Persian invasion of Greece.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Leonidas I, Themistocles.
Side B
1 belligerent
Xerxes I.