Harrowing of Hell
According to David Leeming, writing in "The Oxford Companion to World Mythology", the harrowing of hell is an example of the motif of the hero's descent to the underworld, which is common in many mythologies. According to Christian tradition, Christ descended to hell after his death in order to free the souls there; this event is known as the Harrowing of Hell. This story is narrated in the Gospel of Nicodemus and may be the meaning behind 1 Peter 3:18-22.