Thermopylae
2 of the 7 encyclopedias on this shelf carry an entry for Thermopylae. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
ther-mop'i-le, a narrow pass on the eastern coast of Greece. The mountains leave a pass between themselves and the sea so narrow that two carts can hardly pass on firm ground. The name signifies the hot gates. It is derived from a number of hot springs that burst out at the foot of the cliff. Xerxes, the successor of Darius, whose forces were routed at Marathon, invaded Greece again in 480 B. C., this time by way of the Hellespont and Thrace. The Athenians were shamefully deserted before the battle of Marathon, but the Spartans now took the lead in opposing Xerxes. They mustered a force of allies at the famous pass, where the cliffs protected their left and a Greek fleet, largely Athenian, kept their right wing. For three days the battle raged. A storm destroyed 400 Persian ships and Xerxes could not win the pass. Finally a traitor led a force of the enemy through an obscure path over the mountains; the Spartan leader, Leonidas, now gave his allies leave to retire. He, with a Spartan band of 300, held the pass. Xerxes called upon the Spartans to give up their arms. "Come and take them," was the reply. "The Persians are so numerous that the flight of their arrows and javelins will throw a shadow like a cloud," said one. "Then we will fight in the shade," was the reply. Leonidas and his band supported by 700 Thespians held the Persians at bay for a time, but were finally overpowered by numbers and were slain to a man. The bodies of 300 were burned where they fell. A memorial inscription ran thus, "Stranger, go tell at Sparta that we lie here in obedience to her command."
1000 Classical Characters (1900)
A narrow pass leading from Thessaly into Locris and Phocis, celebrated for a battle fought there, B. C. 480, between Xerxes and the Greeks, in which three hundred Spartans, commanded by Leonidas , resisted for three successive days an enormous Persian army. Lord Byron, in his Childe Harold, canto ii., in an apostrophe to Greece, thus refers to the famous conflict: "Who now shall lead thy scatter'd children forth, And long-accustom'd bondage uncreate ? Not such thy sons who whilome did await, The hopeless warriors of a willing doom, In bleak Thermopylae's sepulchral strait. Oh! who that gallant spirit shall resume, Leap from Eurotas' banks, and call thee from the tomb?"