Erebus is a primordial deity, born of chaos, and the personification of darkness. Hesiod's Theogony identifies Erebus as one of the first five beings in exiestence and he is often refered to as a Titan. It lay between Earth and Hades (Hell) and between Earth and Heaven, where all dead must pass immediately after dying. It is often refered to colloquially as the Abyss, but was known by ancient Qabalists as Sheol or Tehom. When the Catholic Chruch adopted the Greek concepts of Heaven and Hell, Erebus became known as Limbo. Erebus is situated on the outer edge of Hell.
This region was later known as the Fields of Asphodel, a realm to which the vast majority of people who were held to have deserved neither the Elysian Fields (Heaven) nor Tartarus (Hell) were consigned for eternity. When adopted by later Christian's it became known as Abraham's Bosom, and is thought to have held the souls of those who died without salvation, but were not condemned to torment in Hell.