Capricorn, the "Sea-Goat", is a constellation, one of the twelve Signs of the Zodiac. Its appearance was thought to be like that of a mythical creature half goat, half fish. Its Latin name, Capricornus, is simply a derived translation of the Greek aigókerōs goat-horned, "having horns like a goat's horns", "goat horn" or "horned goat". It is the tenth astrological sign, and comes between Sagittarius the Archer and Aquarius the Water-Bearer. As a sun sign, it represents the dates of December 23 through January 20.
The origins of Capricorn mythology are practically unknown. The ancient Greeks had sea-goats, but very little was told about them. Chronos, the god of time, and much later the jealous father of the Greek gods, is the creator of the immortal the sea-goat Pricus, who shares Chronos's ability to manipulate time. Pricus is the father of the race of sea-goats, who are known to be intelligent and honorable creatures who live in the sea near the shore. They can speak and think and are favored by the gods. When the children of Priscus, the younger sea-goats, are naturally drawn by curiosity to the shore, they find their way onto the shore. They can use their front goat legs to pull themselves onto the beach and lay in the sun. But the longer they stay on shore, the more they change from sea-goats into regular goats. Their fish tails become hind legs and they lose their ability to think and speak, essentially becoming like the goats we see today.
This grieves Pricus. As the father of the race of sea-goats, he is determined to make sure his children never get to the shore. He fears that if they do, they will become mindless animals who can never return to the sea. After losing several of his children forever to the land, Pricus decides to reverse time to force his children to return to the sea. Everything on earth, except Pricus, reverses to its previous state, and all of the goats revert back to the time to what they were before they came up on the land.
Pricus, the only one who knows what is to become of the sea-goats tries to warn them, even forbidding them to set foot onto the shore, but no matter what he does, or how many times he reverses time, the sea-goats still eventually find their way onto land. Pricus finally realizes that he cannot control the destiny of his children, and instead unhappily lets his children live out their lives according to their own destiny, and all of them become ordinary goats. In his misery, Pricus begs Chronos to let him die, because he cannot bear to be the only sea-goat left. But because he cannot die, being immortal, Chronos instead takes him off the earth and allows him to live out his immortality in the sky, as the constellation Capricorn.
Greek mythology also identified the constellation of Capricorn as Amalthea or Amalthia, who was either a Mountain Goat or goat-tending nymph. She acted as a foster mother to Zeus as a baby when his mother Rhea stowed him away in the mountains of Crete, saving him from being eaten by his father Cronos, who devoured all his babies after birth by swallowing them whole, when she substituted a blanket-wrapped stone for him to swallow. Amalthea nourished Zeus with her milk, and legend says that as the child Zeus played with Amalthea he accidentally broke off one of her goat's horns, which he then transformed into Cornucopia, the Horn of Plenty, an eternal symbol of abundance, always full of whatever its owner desires. Amalthea raised him until with the help of the Titans and the Cyclopes he defeated and killed Chronos and his forces, and opened Chronos' body, releasing his brothers and sisters, and together they then became the Greek gods of Olympus. In gratitude Zeus made Amalthea immortal and placed her in the sky.
Capricorn may also be part of an imaginative commemoration in the Greek memory of the conquests of Alexander the Great "the great horned goat" who crossed the Hellespont to defeat Darius III of Persia at the Battle of Issus 333 B.C.. See Daniel 8:5-8.