"What Diomede, or Thetis' greater son, A thousand ships, nor ten years seige had done, False fears, and fawning words, the city won"

Thetis dipping Achilles in the River Styx
Public DomainThetis dipping Achilles in the River Styx - Credit: Frans and Jan Raes, 1600s
Thetis (disposer, or the one who places), is depicted in Greek mythology as a goddess of water, one of the fifty Nereids, daughters of the ancient one of the seas.  She was one of the earliest of deities worshiped in archaic Greece. The wedding of Thetis and the Greek hero Peleus is one of the events leading up to the Trojan War.

Thetis Giving Achilles His Arms
Public DomainThetis Giving Achilles His Arms - Credit: Guilio Romano, 1500s

Thetis and Peleus’ son is Achilles.  Homer's Iliad tells of Achilles' deeds in the Trojan War. Achilles' wrath is the central theme of the book. Achilles withdraws from battle after he is dishonored by the Greek leader Agamemnon.  As the Greek forces are beaten back by the Trojans, it becomes clear to all that only Achilles can save the day.  This he does, when his friend Patroclus is killed in battle.  Achilles storms onto the battle field killing all in his path, and finally killing Hector, leader of the Trojans.