Vergil.
It is said that Palamedes was the inventor of weights and measures, and of the games of chess and backgammon, and that it was he who first placed sentinels round a camp and gave them a watchword.
There was another of the Greek princes whose help in the Trojan War was obtained only by an ingenious trick. This was the famous A-chilʹles. He was the son of Peleus and Thetis, at whose marriage feast Eris threw the apple of discord on the table. The prophecy that Thetis would have a son greater than his father was fulfilled in Achilles, the bravest of the Greeks at the Trojan War, and the principal hero of Homer's Iliad.
Thetis educated her son with great care. She had him instructed in all the accomplishments fitting for princes of those times. When he was an infant she dipped him in the river Styx, which, it was believed, made it impossible for any weapon wielded by mortal hands to wound him. But the water did not touch the child's heel by which his mother held him when she plunged him in the river, and it was in this part that he received the wound of which he died.
Notwithstanding his being dipped in the Styx, Thetis was afraid to let Achilles go to the Trojan War, for Jupiter had told her that he would be killed if he took part in it. For this reason, as soon as she heard that the Grecian princes were gathering their forces, she secretly sent the youth to the court of Lyc-o-meʹdes, king of the island of Scyʹros. Here Achilles, dressed like a young girl, resided as a companion of the king's daughters. But Calʹchas, the soothsayer of the Grecian army, told the chiefs that without the help of Achilles Troy could not be taken.
Calchas the wise, the Grecian priest and guide,
That sacred seer, whose comprehensive view,
The past, the present, and the future knew.
Pope, Iliad, Book I.
Calchas, however, could not tell where Achilles was to be found, and when they applied to Peleus, he too was unable or unwilling to tell them. In this difficulty the wily king of Ithaca did good service. After much inquiry he discovered that Achilles was at Scyros with the king's daughters. He soon made his way to the island, but here there was a new difficulty. He had never seen the young prince, and how was he to know him? But he devised a scheme which proved entirely successful. Equipping himself as a peddler, he went to the royal palace, exhibiting jewelry and other fancy articles to attract the attention of the ladies of the family. He also had some beautiful weapons of war among his wares.
Achilles at the Court of Lycomedes.
Painting by Battoni.