In Assassin's Creed Origins, Bayek's home at the beginning of the game is Siwa.
Siwa is an oasis in Egypt's Western Desert and is the home of Bayek, the game's protagonist. Bayek is a Medjay, a protector and law-enforcement figure, and his personal story begins in Siwa before expanding across Ptolemaic Egypt. The oasis introduces the player to the game's setting, combat, investigation systems, and political conflict.
Alexandria, Memphis, and Thebes are also important Egyptian places, but none is Bayek's home at the opening of Origins. Alexandria is particularly prominent because of its intellectual and political importance under Cleopatra and Ptolemy XIII. Origins is set in the first century BCE and depicts the early formation of the Hidden Ones, the organization that later develops into the Assassin Brotherhood.