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The Legend of Laocoön
The most detailed description of Laocoön's grisly fate was provided by Quintus Smyrnaeus in Posthomerica, a later, literary version of events following the Iliad. According to Quintus, Laocoön begged the Trojans to set fire to the horse to ensure it was not a trick. Athena, angry with him and the Trojans, shook the ground around Laocoön's feet and painfully blinded him. The Trojans, watching this unfold, assumed Laocoön was punished for the Trojans' mutilating and doubting Sinon, the undercover Greek soldier sent to convince the Trojans to let him and the horse inside their city walls. Thus, the Trojans wheeled the great wooden Horse in. Laocoön did not give up trying to convince the Trojans to burn the horse, and Athena made him pay even further. She sent two giant sea serpents to strangle and kill him and his two sons. In another version of the story, it was said that Poseidon sent the sea serpents to strangle and kill Laocoön and his two sons. -- Wikipedia
The Laocoön Sculpture
"The statue of Laocoön and His Sons has been one of the most famous ancient sculptures ever since it was excavated in Rome in 1506 and placed on public display in the Vatican, where it remains. It is very likely the same statue as that praised in the highest terms by the main Roman writer on art, Pliny the Elder. The figures are near life-size and the group is a little over 2 meters in height, showing the Trojan priest Laocoön and his sons Antiphantes and Thymbraeus being attacked by sea serpents.
"The group has been called "the prototypical icon of human agony" in Western art, and unlike the agony often depicted in Christian art showing the Passion of Jesus and martyrs, this suffering has no redemptive power or reward. The suffering is shown through the contorted expressions of the faces, which are matched by the struggling bodies, especially that of Laocoön himself, with every part of his body straining." -- Wikipedia (edited)