Bayek's grandfather

The grandfather of Bayek served as a respected Medjay of Siwa, Egypt sometime around the beginning of the 1st century BCE, for this was a hereditary position passed down through his family for generations. His son, Sabu, therefore succeeded to the role after him, as did his grandson, Bayek, after Sabu.

Upon his death, Bayek's grandfather was mummified and buried in the Medjay tomb in the Mountain of the Dead. In 48 BCE, upon Bayek's return to Siwa after a year abroad on his quest of vengeance, he paid his respects to his grandfather.

Reference

 * Assassin's Creed: Origins