James said: It was interesting, when did the idea of after life began ask by Freeman.
The Egyptians believed in an after life before Christianity was invented. The Christians have adopted and then adapted a lot of Pagan beliefs. Christmas, for example, is the Pagan holiday Yule and the celebration of the 'birth of the sun' aka the Winter Solstice. Christians changed the date slightly and called it 'the birth of the son'.
If you want to convince people of a certain faith to convert to yours, I guess you have to adopt some or maybe most to all of the other faiths' traditions. And then, when they don't convert, threaten and torture them until they do.