Poseidon was, like Zeus and Hades, A son of Cronus, after helping to defeat his father he was given the oceans to rule as his domain. He was also known as the creator of the first horse as well as the bringer of earth quakes, which where usually the result of his anger during a argument over who controlled the land.
Apoxyomenos (athlete scraping his body with a strigil). Bronze. Roman copy of the bronze original by Polykleitos ca. 320 B.C.
Rear view. Hylas. 1846. H.W.Bissen
Achilles and Patroclus Achilles, son of Thetis mourns Patroclus, his best friend/lover/ or both it's unsure, Greeks had a tradition of Pederasty which was used to engender this kind of relationship. to encourage warriors in battle.