Instead of now giving up Helen, Deiphobus and Helenus, the two next brothers, quarrelled as to which should marry her, and when she was given to Deiphobus, Helenus was so angry that he went out and wandered in the forests of Mount Ida, where he was made prisoner by Ulysses, who contrived to find out from him that Troy could never be taken while it had the Palladium within it.  Accordingly, Ulysses and Diomed set out, and, climbing over the wall by night, stole the wondrous image.  While the Trojans were dismayed at the loss, the Greeks seemed to have changed their minds.  They took ship and went away, and all the surviving Trojans, relieved from their siege, rushed down to the shore, where all they found was a monstrous wooden horse.  While they were looking at it in wonder, a Greek came out of the rocks, and told them that his name was Sinon, and that he had been cruelly left behind by the Greeks, who had grown weary of the siege and gone home, but that if the wonderful horse were once taken into Troy it would serve as another Palladium.  The priest of Neptune, Laocöon, did not believe the story, and declared that Sinon was a spy; but he was cut short in his remonstrance by two huge serpents, which glided out of the sea and devoured him and his two sons. Cassandra, too, a daughter of Priam, who had the gift of prophecy, but was fated never to be believed, shrieked with despair when she saw the Trojans harnessing themselves to the horse to drag it into Troy, but nobody heeded her, and there was a great feast to dedicate it to Pallas. Helen perhaps guessed or knew what it meant, for at dark she walked round it, and called the names of Ulysses, and many other Greeks, in the voices of Penelope and the other wives at home.