In Assassin's Creed Origins, Bayek begins his journey in the Egyptian oasis settlement of Siwa.
Siwa is a remote oasis in Egypt's Western Desert and is the home of Bayek, who serves as a medjay. The opening chapters establish his personal quest and introduce the political and religious tensions that shape the game's Ptolemaic setting. From Siwa, Bayek travels across Egypt while pursuing members of the Order of the Ancients.
The game's map later includes major locations such as Alexandria, Memphis, Cyrene, and Giza. Alexandria is the large Mediterranean city associated with Greek and Egyptian intellectual life, but it is not Bayek's starting settlement. Memphis is another major city reached during the story.
Origins uses Bayek's investigation to show the early formation of the Hidden Ones, the organization that later develops into the Assassin Brotherhood. Siwa therefore has both geographical importance and personal significance in the narrative.