Forensic and archaeological expert Andrew Wilson from the University of Bradford led different studies on three mummies found on a volcano, and he declared that the oldest female is the world's best-preserved mummy. The Inca civilization used human sacrifices to honor important events such as the birth of the emperor's son, the return of victorious Inca armies, or natural disasters. In the case of the death of a ruler, the necropompa was performed to provide the deceased with servants in the afterlife.