Watch 300 Spartans: The Real Story Full Movie Free Online 123Movies. 300 Spartans-The Real Story. Putting aside the myths and legends, this documentary takes a detailed look at the Battle of Thermopylae in 480 BC Greece leading to the last stand of the 300 Spartans and Spartan King Leonidas. On the 3rd day of the battle, when Leonidas was being surrounded, he sent most of his troops away and covered their retreat with a last stand because Spartans never retreated.