Ancient Egypt. Almost everything that the world has left of this fallen civilization is tied directly to their tombs. Of all the world's great civilizations, the ancient Egyptians had, perhaps, the most well-developed funerary tradition, and their beliefs in the afterlife were tied to beliefs in a complex species of soul.
In the cosmology of ancient Egypt, each individual was thought to possess not one, but several spirits. There was the Akh, the immortal spirit, typically represented by a glyph that resembled the Benu bird — the inspiration for the Greek Phoenix. There was the Ba, a winged spirit with the body of a bird and the head of a man, which flew forth from the corpse upon death. And then there was the Ka, whose hieroglyph was two upraised arms. The image of the Ka, depicted on the left, is shown wearing its hieroglyph like a crown. In modern occult writings, the Ka is often equated with the metaphysical notion of the Body Double, the portion of the self fundamental to astral projection. This spirit was the perfect twin of the deceased, and it was believed to remain lingering in the tomb, tied to the mortal remains so carefully mummified by Egyptian morticians.