In Greek mythology, Idomeneus was a Cretan king who led eighty black ships to the Trojan War. Grandson of Minos and son of Deucalion of Crete, he ranks among Homer's front-line Achaean commanders and Helen's suitors; Meriones is his charioteer and brother-in-arms. Later traditions send him into exile after a storm-vow that costs his son's life, or after his foster-son Leucus usurps Crete.
Adapted from Wikipedia, "Idomeneus" · CC BY-SA 4.0
I.Family
Idomeneus is son of Deucalion (himself son of Minos and Pasiphaë) and, in some notices, Cleopatra — thus a great-grandson of Helios through Pasiphaë. He is husband of Meda and father of children including Orsilochus. His Cretan grandfather Deucalion must not be confused with Deucalion the flood survivor, father of Hellen.
As a former suitor of Helen he was bound by the Oath of Tyndareus to join the expedition against Troy.
II.At Troy
In the Iliad Idomeneus fights in the first rank, advises Agamemnon, and holds the line when other heroes are wounded; he briefly faces Hector and is among those said to enter the Wooden Horse. Meriones fights beside him. Later epic tallies give him many Trojan kills, including Amazons in Quintus of Smyrna.
Homer leaves him alive at the war's end; the return stories belong to post-Homeric tradition.
III.Return and exile
Servius, commenting on Virgil, tells that a storm on the homeward voyage led Idomeneus to vow to Poseidon the first living thing he saw on landing — his own son. The sacrifice brought plague; the Cretans drove him to Calabria and later Colophon. Varro connects Salentine peoples with his landing.
Apollodorus instead has Leucus, his foster-son, seduce and kill Meda and seize the throne, forcing Idomeneus out. Mozart's Idomeneo adapts the vow-story so that Neptune spares the son if the king yields the crown.