How were the Greeks finally able to defeat the Trojan's?

The Greeks were able to defeat the Trojans through the clever stratagem of the Trojan Horse. After a long and fruitless siege of Troy, the Greeks constructed a large wooden horse, hiding soldiers inside, and left it at the gates of the city as a supposed offering to the gods. The Trojans, believing they had won, brought the horse into the city, celebrating their victory. That night, the Greek soldiers emerged from the horse, opened the gates for the rest of the Greek army, and ultimately led to the fall of Troy.