Paris, after seducing Helen while a guest in the palace of her husband, King Menelaus of Sparta, went blithely on his way back to Troy with Helen. This abduction and violation of all rules of hospitality launched 1000 (Greek) ships to bring Helen back to Menelaus. Meanwhile, King Agamemnon of Mycenae, summoned the tribal kings from all over Greece to come to the aid of his cuckolded brother.
Two of his best men -- one a strategist and the other a great warrior -- were Odysseus (aka Ulysses) of Ithaca, who would later come up with the idea of the Trojan Horse, and Achilles of Phthia, who may have married Helen in the Afterlife. Neither of these men wanted to join the fray; so they each devised a draft-dodging ruse worthy of M.A.S.H.'s Klinger.
Odysseus feigned madness by plowing his field destructively, perhaps with mismatched draft animals, perhaps with salt (a powerful destructive agent used according to legend at least one other time -- by the Romans on Carthage). Agamemnon's messenger placed Telemachus, Odysseus' infant son, on the path of the plough. When Odysseus swerved to avoid killing him, he was recognized as sane.
Achilles -- with blame for cowardice conveniently laid at the feet of his mother, Thetis -- was made to look like and live with the maidens. Odysseus tricked him with the lure of a peddler's bag of trinkets. All the other maidens reached for the ornaments, but Achilles grabbed the sword stuck in their midst. The Greek (Achaean) leaders met together at Aulis where they awaited Agamemnon's command to set sail. When an inordinate amount of time had passed and the winds still remained unfavorable, Agamemnon sought the services of Calchas the seer. Calchas told him that Artemis was angry with Agamemnon -- perhaps because he had promised her his finest sheep as a sacrifice to the goddess, but when the time came to sacrifice a golden sheep, he had, instead, substituted an ordinary one -- and to appease her, Agamemnon must sacrifice his daughter Iphigenia ....
Upon the death of Iphigenia, the winds became favorable and the fleet set sail.