The war originated from a quarrel between the goddesses Athena, Hera, and Aphrodite, after Eris, the goddess of strife and discord, gave them a golden apple, sometimes known as the Apple of Discord, marked "for the fairest". Zeus sent the goddesses to Paris, who judged that Aphrodite, as the "fairest", should receive the apple. In exchange, Aphrodite made Helen, the most beautiful of all women and wife of Menelaus, fall in love with Paris, who took her to Troy. Agamemnon, king of Mycenae and the brother of Helen's husband Menelaus, led an expedition of Achaean troops to Troy and besieged the city for ten years because of Paris' insult. After the deaths of many heroes, including the Achaeans Achilles and Ajax, and the Trojans Hector and Paris, the city fell to the ruse of the Trojan Horse. The Achaeans slaughtered the Trojans (except for some of the women and children whom they kept or sold as slaves) and desecrated the temples, thus earning the gods' wrath. Few of the Achaeans returned safely to their homes and many founded colonies in distant shores. The Romans later traced their origin to Aeneas, one of the Trojans, who was said to have led the surviving Trojans to modern-day Italy.
The ancient Greeks treated the Trojan War as an historical event which had taken place in the 13th or 12th century BC, and believed that Troy was located in modern-day Turkey near the Dardanelles. As of the mid-19th century, both the war and the city were widely believed to be non-historical. In 1868, however, the German archaeologist Heinrich Schliemann met Frank Calvert, who convinced Schliemann that Troy was at Hissarlik and Schliemann took over Calvert's excavations on property belonging to Calvert; this claim is now accepted by most scholars. Whether there is any historical reality behind the Trojan War is 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 centuries BC, often preferring the dates given by Eratosthenes, 1194–1184 BC, which roughly corresponds with archaeological evidence of a catastrophic burning of Troy VII.