Which Assassin's Creed game introduced the setting of ancient Greece?

Assassin's Creed Odyssey introduced ancient Greece as the series' main historical setting.

Ubisoft released Assassin's Creed Odyssey in 2018. The game takes place during the Peloponnesian War in the 5th century BCE and allows the player to follow either Kassandra or Alexios as the playable mercenary. Its large map includes mainland Greece and numerous Aegean islands.

Odyssey expands the role-playing systems introduced in earlier entries, including dialogue choices, branching outcomes, equipment rarity, and naval travel. It also explores the history of the First Civilization and the relationship between the playable character and the legendary Spear of Leonidas.

Assassin's Creed Origins is the common alternative answer because it introduced ancient Egypt, not Greece. Assassin's Creed Valhalla focuses on Viking-era England and Norway, while Assassin's Creed Mirage is set mainly in 9th-century Baghdad. Odyssey therefore identifies the Greek setting specifically.