As Egypt gained more prosperity, burial practices became a status symbol for the wealthy as well.
This cultural hierarchy lead to the creation of elaborate tombs, and more sophisticated methods of embalming.
Spontaneous mummies, such as Ötzi, were created unintentionally due to natural conditions such as extremely dry heat or cold, or anaerobic conditions such as those found in bogs.
While most individual mummies exclusively belong to one category or the other, there are examples of both types being connected to a single culture, such as those from the ancient Egyptian culture and the Andean cultures of South America.
The Spirit Cave mummies of Fallon, Nevada in North America were accurately dated at more than 9,400 years old.
Before this discovery, the oldest known deliberate mummy was a child, one of the Chinchorro mummies found in the Camarones Valley, Chile, which dates around 5050 BC.
Anthropogenic mummies were deliberately created by the living for any number of reasons, the most common being for religious purposes.
By utilizing current advancements in technology, scientists have been able to uncover a plethora of new information about the techniques used in mummification.
A series of CT scans performed on a 2,400-year-old mummy in 2008 revealed a tool that was left inside the cranial cavity of the skull.
Egyptians buried the dead in pit graves, without regard to social status. This characteristic allowed for the hot, dry sand of the desert to dehydrate the bodies, leading to natural mummification.
The natural preservation of the dead had a profound effect on ancient Egyptian religion.
The first modern scientific examinations of mummies began in 1901, conducted by professors at the English-language Government School of Medicine in Cairo, Egypt.