POSEIDON (Neptune) was the Lord and Ruler of the Sea (the Mediterranean) and the Friendly Sea (the Euxine, now the Black Sea). Underground rivers, too, were his.
OCEAN, a Titan, was Lord of the river Ocean, a great river encircling the earth. His wife, also a Titan, was Tethys. The Oceanids, the nymphs of this great river, were their daughters. The gods of all the rivers on earth were their sons.
PONTUS, which means the Deep Sea, was a son of Mother Earth and the father of Nereus, a sea-god far more important than he himself was.
NEREUS was called the Old Man of the Sea (the Mediterranean)—“A trusty god and gentle,” Hesiod says, “who thinks just and kindly thoughts and never lies.” His wife was Doris, a daughter of Ocean. They had fifty lovely daughters, the nymphs of the Sea, called NEREIDS from their father’s name, one of whom, Thetis, was the mother of Achilles. Poseidon’s wife, AMPHITRITE, was another.
TRITON was the trumpeter of the Sea. His trumpet was a great shell. He was the son of Poseidon and Amphitrite.
PROTEUS was sometimes said to be Poseidon’s son, sometimes his attendant. He had the power both of foretelling the future and of changing his shape at will.
THE NAIADS were also water nymphs. They dwelt in brooks and springs and fountains.
LEUCOTHEA and her son PALAEMON, once mortals, became divinities of the sea, as did also GLAUCUS, but all three were unimportant.