Excerpt from Apollodorus's Library Book 5: 13-
The Story of the Trojan Horse
5.13: And Ulysses went with Diomedes by night to the city, and there he let Diomedes wait, and after disfiguring himself and putting on mean attire he entered unknown into the city as a beggar. And being recognized by Helen, he with her help stole away the Palladium, and after killing many of the guards, brought it to the ships with the aid of Diomedes.
5:14 But afterwards he invented the construction of the Wooden Horse and suggested it to Epeus, who was an architect. Epeus felled timber on Ida, and constructed the horse with a hollow interior and an opening in the sides. Into this horse Ulysses persuaded fifty ( or, according to the author of the Little Iliad, three thousand) of the doughtiest to enter, while the rest, when night had fallen, were to burn their tents, and, putting to sea, to lie to off Tenedos, but to sail back to land after the ensuing night.
5:15 They followed the advice of Ulysses and introduced the doughtiest into the horse, after appointing Ulysses their leader and engraving on the horse an inscription which signified, “ For their return home, the Greeks dedicate this thank--offering to Athena.” But they themselves burned their tents, and leaving Sinon, who was to light a beacon as a signal to them, they put to sea by night, and lay to off Tenedos. (Note below in this 7th century vase, the heads of the Greeks in the body of the horse.
.5:16 And at break of day, when the Trojans beheld the camp of the Greeks deserted and believed that they had fled, they with great joy dragged the horse, and stationing it beside the palace of Priam deliberated what they should do.
5:17 As Cassandra said that there was an armed force in it, and she was further confirmed by Laocoon, the seer, some were for burning it, and others for throwing it down a precipice; but as most were in favour of sparing it as a votive offering sacred to a divinity, they betook them to sacrifice and feasting.
5:18 However, Apollo sent them a sign; for two serpents swam through the sea from the neighboring islands and devoured the sons of Laocoon.(see image below of famous Hellenistic sculpture of this story)
5:19 And when night fell, and all were plunged in sleep, the Greeks drew near by sea from Tenedos, and Sinon kindled the beacon on the grave of Achilles to guide them. And Helen, going round the horse, called the chiefs, imitating the voices of each of their wives. But when Anticlus would have answered, Ulysses held fast his mouth.
5:20 and when they thought that their foes were asleep, they opened the horse and came forth with their arms. The first, Echion, son of Portheus, was killed by leaping from it; but the rest let themselves down by a rope, and lighted on the walls, and having opened the gates they admitted their comrades who had landed from Tenedos.
5:21 And marching, arms in hand, into the city, they entered the houses and slew the sleepers. Neoptolemus slew Priam, who had taken refuge at the altar of Zeus of the Courtyard. But when Glaucus, son of Antenor, fled to his house, Ulysses and Menelaus recognized and rescued him by their armed intervention. Aeneas took up his father Anchises and fled, and the Greeks let him alone on account of his piety.
5:22 But Menelaus slew Deiphobus and led away Helen to the ships ; and Aethra, mother of Theseus, was also led away by Demophon and Acamas, the sons of Theseus; for they say that they afterwards went to Troy. And the Locrian Ajax, seeing Cassandra clinging to the wooden image of Athena, violated her; therefore they say that the image looks to heaven.(see fourth century vase painting of Ajax raping Cassandra below).
5:23 And having slain the Trojans, they set fire to the city and divided the spoil among them. And having sacrificed to all the gods, they threw Astyanax from the battlements and slaughtered Polyxena on the grave of Achilles. And as special awards Agamemnon got Cassandra, Neoptolemus got Andromache, and Ulysses got Hecuba. But some say that Helenus got her, and crossed over with her to the Chersonese; and that there she turned into a bitch, and he buried her at the place now called the Bitch's Tomb. As for Laodice, the fairest of the daughters of Priam, she was swallowed up by a chasm in the earth in the sight of all. When they had laid Troy waste and were about to sail away, they were detained by Calchas, who said that Athena was angry with them on account of the impiety of Ajax. And they would have killed Ajax, but he fled to the altar and they let him alone.
Text from Internet Source: Perseus