Which studio led development of the original 2007 Assassin's Creed game?

Ubisoft Montreal led development of the original 2007 Assassin's Creed game. The Canadian studio created the title for Ubisoft, with additional contributions from other Ubisoft teams and external partners.

Ubisoft Montreal is based in Montreal, Quebec, and became closely associated with the early Assassin's Creed series. Its work on the first game established the franchise's core combination of historical cities, free-running, stealth, social blending, and close-quarters combat.

Ubisoft Quebec later led development of Assassin's Creed Syndicate and Assassin's Creed Odyssey, while Ubisoft Sofia contributed to Assassin's Creed Rogue and other projects. Those studios are therefore plausible answers when discussing the wider franchise, but they did not lead the original game's development. Ubisoft Montreal's role belongs specifically to the 2007 debut.