Short answers, pulled from the story.
The Chinchorro culture performed artificial mummification as early as 5000 to 6000 BCE. This practice predates Egyptian methods by thousands of years and remains largely unknown outside specialized archaeological circles.
Ancient Egyptians covered bodies with natron, a mixture of desiccating salts found naturally in the Wadi El Natrun west of the Nile Delta. The process involved removing organs and ridding the body of moisture before applying these salts.
William Hunter became the first to apply arterial injection methods to mortuary practice in the late 18th century. He wrote a widely read report on appropriate methods for arterial and cavity embalming to preserve bodies for burial.
Embalming became common in the United States during the American Civil War when servicemen often died far from home. Dr Thomas Holmes received a commission from the Army Medical Corps to embalm dead Union officers so they could be returned to their families.
Traditional Jewish law forbids embalming entirely, requiring burial within 24 hours if possible. Members of the Bahá'í Faith are not embalmed, and Muslims bury deceased without delay to allow the soul to transition to the afterlife as soon as possible.