In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans (Greeks) after Paris of Troy took Helen from her husband Menelaus, king of Sparta. The war is one of the most important events in Greek mythology and has been narrated through many works of Greek literature, most notably Homer's Iliad. The core of the Iliad (Books II – XXIII) describes a period of four days and two nights in the tenth year of the decade-long siege of Troy; the Odyssey describes the journey home of Odysseus, one of the war's heroes. Other parts of the war are described in a cycle of epic poems, which have survived through fragments. Episodes from the war provided material for Greek tragedy and other works of Greek literature, and for Roman poets including Virgil and Ovid.

The ancient Greeks believed that Troy was located near the Dardanelles and that the Trojan War was a historical event of the 13th or 12th century BC, but by the mid-19th century AD, both the war and the city were widely seen as non-historical. In 1868, however, the German archaeologist Heinrich Schliemann met Frank Calvert, who convinced Schliemann that Troy was a real city at what is now Hisarlik in Turkey. On the basis of excavations conducted by Schliemann and others, this claim is now accepted by most scholars.Whether there is any historical reality behind the Trojan War remains an open question. Many scholars believe that there is a historical core to the tale, though this may simply mean that the Homeric stories are a fusion of various tales of sieges and expeditions by Mycenaean Greeks during the Bronze Age. Those who believe that the stories of the Trojan War are derived from a specific historical conflict usually date it to the 12th or 11th century BC, often preferring the dates given by Eratosthenes, 1194–1184 BC, which roughly correspond to archaeological evidence of a catastrophic burning of Troy VII, and the Late Bronze Age collapse.