Nine cities found one beneath another were originally excavated by Heinrich Schliemann 1874-90. The first fortifications appeared on the site in the Early Bronze Age. These were a stone wall with a mudbrick battlement and a gate protected by flanking towers. By the Middle Bronze Age the defences had been enlarged and required at least four gateways, two of which were protected by towers. Recent research suggests that the seventh, sacked and burned about 1270 BC, is probably the Homeric Troy. The city and its defences were rebuilt, but suffered a similar fate about 1050 BC. These two destructions, of Troy VI and VIII respectively, have been suggested as the sack of the city in the Trojan War related by the Greek poet Homer. The city of Ilium was built on the same site in the 7th century BC, and survived to the Roman period.

In Homer's war tale, Troy fell to the Greeks who, in a feigned retreat, left behind a large wooden horse. Believing it to be a religious offering, the Trojans took it within the city walls. Armed infiltrators hiding inside the horse later emerged to open the gates to the Greeks who sacked and burned the city. The tale may have had a basis in fact, for example, a conflict arising from trade rivalry (Troy was on a tin trade route) might have been triggered by such an incident as Paris running off with Helen. The wooden horse could have been a votive offering for Poseidon whose emblem was a horse, left behind by the Greeks after an earthquake opened breaches in the city walls.