Poseidon was one of three sons of Cronus and Rhea. Together with his brothers, Zeus and Hades, Poseidon ruled over the world. Cronus was in the habit of swallowing his children, and his three remaining sons were fed up... so to speak. According to legend, Poseidon and his brothers defeated Cronus and freed their siblings. Then the three brothers divvied up the world. Poseidon got the sea, Zeus got the heavens, and Hades inherited the underworld. They decided to share the earth.
A dysfunctional family from the start, relations continued to deteriorate after Poseidon summoned a sea monster to collect back pay. Posiedon also waged running feuds with Athena, Hera, Zeus, and Dionysus. Usually he lost the argument and the battle. But no one ever disputed Poseidon's right to rule the seas.
With his trident he commanded waves, caused storms, wrought earthquakes, sunk boats. and caused springs to flow.
And he had a special relationship with dolphins.
But Poseidon was lucky in love. He fell in love the first time he saw Amphitrite dancing with her sisters. When he asked for her hand in marriage, she refused and hid in the forest, so Poseidon sent a dolphin to look for her. The dolphin not only found Amphitrite; he convinced her to marry Poseidon.
As a reward, Poseidon placed the dolphin in a constellation, and Poseidon and Amphitrite lived happily ever after.
Some helpful dolphins for you.