The ancient Egyptians were known to mummify their Pharaohs and elites. The first Egyptian mummies appeared at approximately three thousand five hundred B.C. By the time of the Old Kingdom, or Age of the Pyramids, mummification was well entrenched in Egyptian society.
Sources:
Bunson, M. The Encyclopedia of Ancient Egypt. Gramercy Books, 1991.
David, R. Handbook to Life in Ancient Egypt. Oxford University Press, 2007.
Gibson, C. The Hidden Life of Ancient Egypt. Saraband, 2009.
Ikram,S. Death and Burial in Ancient Egypt. Longman, 2003.
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Strudwick, H. The Encyclopedia of Ancient Egypt. Metro Books, 2006.