The Trojan Horse is a tale from the Trojan War

Trojan War

In Greek mythology, the Trojan War was waged against the city of Troy by the Achaeans after Paris of Troy took Helen from her husband Menelaus, the king of Sparta. The war is among the most important events in Greek mythology and was narrated in many works of Greek literature, including the Iliad...

 about the stratagem that allowed the Greeks finally to enter the city of Troy

Troy

Troy was a city, both factual and legendary, located in northwest Anatolia in what is now Turkey, southeast of the Dardanelles and beside Mount Ida...

 and end the conflict. In the canonical version, after a fruitless 10-year siege, the Greeks constructed a huge wooden horse

Horse

The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

, and hid a select force of men inside. The Greeks pretended to sail away, and the Trojans pulled the horse into their city as a victory trophy. That night the Greek force crept out of the horse and opened the gates for the rest of the Greek army, which had sailed back under cover of night.