‘Earthquake? … No captain, battle formations…’
The Thermopylae, the hot gates or also gates of fire, is a mountain pass in modern Greece where legend tells that King Leonidas and 300 of his Spartan warriors fought millions of Persians, during Xerxes’ invasion of Greece in 480 B.C. They were able to hold the mountain pass until August 10, when they were betrayed and finally defeated.
At the time of the battle, the slopes of Mount Kallidromon would have been more heavily wooded as today and the sea came right up to the pass. So the Thermopylae were a narrow passage between the high ground and the sea. This location created the perfect bottleneck which would prevent a numerically superior Persian army, with estimated 80,000 to 250,000 soldiers, from overwhelming the much smaller army of Leonidas, consisting of 300 Spartans and 5,000 to 7,000 Greek soldiers. By blocking the way Leonidas slowed down the Persian invasion, giving the Greeks time to retreat and reorganize.
The strategic location of the Thermopylae is no geological coincidence. The passage is located along a large fault zone, crossing the entire Aegean Sea and the Greek peninsula, where the Eurasian plate meets the Aegean microplate. The movements along the plate boundaries formed a series of parallel faults in the Kallidromo Mountains, where a large block of crust moved downwards, forming a tectonic graben. Such normal faults generally occur at angles of 30 to 60 degrees and it is the orientation of the faults that shapes the steep faces of Mount Kallidromon. As the graben was also partially inundated by the sea, forming the Malian gulf, the narrow passage of the Thermopylae formed.
As the Spercheios River deposited sediments in the graben, the sea has been regressing eastwards since 480 B.C. and today a wide coastal plain marks the site of the battle.