But Troy still held out. The Greeks began to despair of subduing it by force, and by advice of Ulysses they resorted to stratagem. They pretended to be making preparations to abandon the siege; and a number of the ships were withdrawn and concealed behind a neighboring island. They then constructed and immense wooden horse, which they gave out was intended as a propitiatory offering to Minerva; but it was, in fact, filled with armed men. The rest of the Greeks then betook themselves to their ships and sailed away, as if for a final departure. The Trojans, seeing the encampment broken up and the fleet gone, concluded that the enemy had abandoned the siege. The gates of the city were thrown open, and the whole population issued forth, rejoicing at the long-prohibited liberty of passing freely over the scene of the late encampment. 

The great horse was the chief object of curiosity. Some recommenced that it be taken into the city as a trophy; others felt afraid of it. While they hesitated, Laocoon, the priest of Neptune, exclaimed, "What madness, citizens, is this! Have you not learned enough of Grecian fraud to be on your guard against it? For my part, I fear the Greeks even when they offer gifts." So saying, he threw his lance at the horse's side. It struck, and a hollow sound reverberated like a groan. Then perhaps the people might have taken his advice and destroyed the fatal horse with its contents, but just at that moment a group of people appeared dragging forward one who seemed a prisoner and a Greek. Stupefied with terror, the captive was brought before the chiefs. He informed them that he was a Greek, Sinon by name, and that in consequence of the malice of Ulysses, he had been left behind by his countrymen at their departure. With regard to the wooden horse, he told them that it was a propitiatory offering to Minerva, and had been made so huge for the express purpose of preventing its being carried within the city; for Calchas the prophet had told them that if the Trojans took possession of it, they would assuredly triumph over the Greeks.

Laocoon and the Serpents

This language turned the tide of the people's feelings, and they began to think how they might best secure the monstrous horse and the favorable auguries connected with it, when suddenly a prodigy occurred which left no room for doubt. There appeared advancing over the sea two immense serpents. They came upon the land and the crowd fled in all directions. The serpents advanced directly to the spot where Lacoon stood with his two sons. They first attacked the children, winding round their bodies and breathing pestilential breath in their faces. The father, attempting to rescue them, was next seized and involved in the serpent's coils.

"The struggle; vain, against the coiling strain
And gripe, and deepening of the dragon's grasp,
The old man's clinch; the long envenomed chain
Rivets the living links,, -- the enormous asp
Enforces pang on pang, and stifles gasp on gasp."

(Byron - Childe Harold)

He struggled to tear them away,, but they overpowered al his efforts and strangled him and the children in their poisonous folds. The event was regarded as a clear indication of the displeasure of the gods at Laocoon's irreverent treatment of the wooden horse, which they no longer hesitated to regard as a sacred object and prepared to introduce with due solemnity into the city. They did so with songs and triumphal acclamations, and the day closed with festivity. In the night, the armed men who were enclosed in the body of the horse, being let out by the traitor Sinon, opened the gates of the city to their friends who had returned under cover of the night. The city was set on fire; the people, overcome with feasting and sleep, were put to the sword, and Troy completely subdued.