In the Epic of Gilgamesh called Enkidu's Dream written around 2000 BC, the bleak concept of death being an express outcome of sins committed in life, there is a very apt reference to kings' "crowns put away forever" and the ones who stood at any worldly position on Earth "stood now like servants". This depicts how the Mesopotamian had an acute belief that the afterlife was merely suffering and distress to say the least and the dead were both pitied and feared.
Furthermore, the references to "vampire foot", "lion's foot" and "eagle's talon" all illustrate the fears that the people of this time had and how they associates all that they feared with the dismal possibility of death and what they figured would happen afterwards.
Contrary to this dreary outlook to life after death of the Mesopotamian people, the Greeks were more optimistic about the afterlife. Although they believed that the people who did wrong on Earth will be punished severely by the gods in the afterlife, they also believed that the good doers will have an eternally peaceful life; modern researchers believe that the concept of heaven and hell originated from this era.
The Myth of ER which is the concluding part of Plato's dialogue called The Republic, talks of a man called ER who dies in battle but remains un-decomposed even after ten days when his body was recovered. Waking up two days later on his unreal pyre, he tells his people about his passage to the afterlife (probably one of the first recounts of out of body experiences) in which he sees that moral people were rewarded and the immoral were castigated in their afterlives.
Many believe that this was the point where the belief that the soul was mere energy and never dies came about and the intervention of a divine being brought about conviction in following religions. Punishment and rewards in the afterlife were considered a direct consequence of one's conduct in life.
The Egyptians were another matter altogether. While both the Greeks and Mesopotamians agreed on the fact that there was a life after death which may either be absolutely bleak or have either a reward or a punishment awaiting them, the Egyptians treated their dead as if they were not dead after all. Elaborate preparations went into the ensuring that a person's ka (soul) and ba (personality) were united and the being would once more surface to travel to the heavens - intact and whole. The body was embalmed for preservation and provisions like writing paper, wigs, clothing and even tools were made available that the dead may need in the afterlife.
The pyramid texts inscribed inside the pyramids of some pharaohs of the fifth and the sixth dynasties are primarily associated with the transition of the dead pharaoh to its heavenly abode. "He is not of the earth, he is of the sky. . . ." depicts this transition in terms of the passage a dead being takes after the incorporation of the ka and the ba. Journey to the next world is imminent and the work continued as if alive!
While both the Mesopotamians and the Greek eloquently believed that death is the end and the after life depicts what we have done in actual life, the Egyptians believed in the re-usage of energy (soul) for the continuation of the same work being done at the time of death. Oddly enough,