Which Assassin's Creed game first used ancient Egypt as its main historical setting?

Assassin's Creed Origins was the first Assassin's Creed game to use ancient Egypt as its main historical setting.

Released in 2017, Origins follows Bayek of Siwa, a Medjay who becomes involved in the early formation of the Hidden Ones, the group that later develops into the Assassin Brotherhood. The story is set during the first century BCE, when Egypt is ruled by Cleopatra and is caught between Roman and Ptolemaic power.

The game depicts locations including Siwa, Alexandria, Memphis, and Giza. It also substantially changes the series' design by adding levels, loot, ability trees, and a more prominent role-playing structure.

Odyssey follows Origins and moves the historical setting to fifth-century BCE Greece. Valhalla is later set mainly in ninth-century England and Norway, while Mirage focuses on ninth-century Baghdad. Those games therefore should not be substituted for Origins when identifying the first ancient-Egypt entry.