The Battle of Thermopylae was a battle between an alliance of the Greek city states lead by the Spartan king King Leonidas ad the Persian Empire of Xerxes I over the course of three days during the second Persian invasion of Greece during the year 480 B.C.. The long path to battle at Thermopylae began in what is now Iran, heart of the once vast Persian empire. Nowadays, ancient ruins attest to its long-vanished greatness, but to the Greeks of the early 5th century B.C., the Persian empire was young, aggressive and dangerous. Persian expansion had begun in the mid-6th century, when its first shah, or great king, Cyrus, had led a revolt against the dominant Medes. By 545 B.C., Cyrus had extended Persian hegemony to the coast of Asia Minor.
According to the Greek historian Herodotus, Darius was especially furious to learn that a distant city called Athens had dared to assist his rebellious subjects in Asia Minor. Grant, O God, he said, shooting an arrow into the air, that I may punish the Athenians. He even commanded one of his servants to interrupt him during every dinner three times to remind him of his goal with the admonition, Master, remember the Athenians. The first Persian War ended badly for Darius, however, when his troops were defeated by a smaller Athenian army at Marathon in 490 B.C.. Greece was saved — but only for a while.
Darius’ son Xerxes does not seem to have been especially driven to complete his late father’s unfinished business. He waffled over whether the long-delayed punishment of Athens merited such a far-flung campaign. At last a phantom allegedly appeared in his dreams, urging him to invade Greece. Xerxes spent more than four years gathering soldiers and stockpiling supplies from every corner of his empire. The resulting host amounted to a colossal cosmopolitan army of armies. In it were Persians, Medes and Hyrcanians, all wearing felt caps, tunics, mail and trousers, and armed with short spears, light wicker shields and deadly,...