12,000 – 10,000 Years Ago – (Egypt), found what seems like shamanistic art in a remote cave, in which art mural of swimmers, possibly swimming off to the afterlife; as water has been viewed as a path to the afterlife, like how baptism is thought to kill the old self and once returning from the under the water. Furthermore, ritualistic art consisting of hand silhouettes and cattle as well as what could be a ceremony maybe even an early paganistic/polytheistic expression as female figures and a row of 10 figures each holding a crescent moon or bull horn over their heads with both hands may even reference afterlife to us are extended. However, it is the swimming figures, possibly to a secret passage, which could illustrate the passage into the afterlife. Death was commonly seen as connected to water or underwater which is why baptism is seen as rebirth or death of the old self by going under the water.
References 1, 2