Hecate (sometimes spelled Hekate) was originally a Thracian, and pre-Olympian Greek goddess, and ruled over the realms of earth and fertility rituals. As a goddess of childbirth, she was often invoked for rites of puberty, and in some cases watched over maidens who were beginning to menstruate. Eventually, Hecate evolved to become a goddess of magic and sorcery. She was venerated as a mother goddess, and during the Ptolemaic period in Alexandria was elevated to her position as goddess of ghosts and the spirit world.
Much like the Celtic hearth goddess Brighid, Hecate is a guardian of crossroads, and often symbolized by a spinning wheel. In addition to her connection to Brighid, she is associated with Diana Lucifera, who is the Roman Diana in her aspect as light-bearer. Hecate is often portrayed wearing the keys to the spirit world at her belt, accompanied by a three-headed hound, and surrounded by lit torches.
The epic poet Hesiod tells us Hecate was the only child of Asteria, a star goddess who was the aunt of Apollo and Artemis. The event of Hecate’s birth was tied to the reappearance of Phoebe, a lunar goddess, who appeared during the darkest phase of the moon.
Today, many contemporary Pagans and Wiccans honor Hecate in her guise as a Dark Goddess, although it would be incorrect to refer to her as an aspect of the Crone, because of her connection to childbirth and maidenhood. It’s more likely that her role as “dark goddess” comes from her connection to the spirit world, ghosts, the dark moon, and magic. She is known as a goddess who is not to be invoked lightly, or by those who are calling upon her frivolously. She is honored on November 30, the night of Hecate Trivia, the night of the crossroads.
[ Source : paganwiccan.about.com ]