What epic included the story of the Trojan horse

The Trojan horse was a ruse the Greeks used to invade Troy. They presented it as a gift to Troy. However, once inside the walls of Troy, an army came out of the horse where they had been hiding and Conquered the guarded city. It is a well known story. The moral being never to accept a gift from your enemies, no matter how great the gift is, for you never know what underlays.