Sinon
Son of Aesimus, or, according to Vergil (Aen. ii. 79), of Sisyphus, and grandson of Autolycus, was a relation of Ulysses, whom he accompanied to Troy. He allowed himself to be taken prisoner by the Trojans, and then persuaded them to admit into their city a wooden horse filled with armed men, which the Greeks had constructed as a pretended atonement for the Palladium. The Trojans believed the deceiver, and dragged the horse into the city; whereupon Sinon in the dead of night let the Greeks out of the horse, who thus took Troy.
Siphnus (Siphno). An island in the Aegean Sea, forming one of the Cyclades. The moral character of the Siphnians stood low, and hence to act like a Siphnian became a term of reproach.
Sirenes (The Sirens). They lured to destruction those who listened to their songs. When Ulysses sailed past their island he stopped the ears of his companions with wax, and had himself tied to the mast of his ship. Thus he passed with safety, and the Sirens, disappointed of their prey, drowned themselves.