Which 2003 video game inspired the original Assassin's Creed concept?

Prince of Persia: The Sands of Time inspired the original Assassin's Creed concept.

The idea for Assassin's Creed developed from a proposed spin-off connected to Prince of Persia: The Sands of Time, which Ubisoft released in 2003. The early concept focused on an elite protector serving a prince, but the project expanded into a separate game with its own setting, characters, and mythology.

The resulting Assassin's Creed replaced the Persian fantasy framework with a historical conflict between the Assassins and Templars. It introduced Altaïr Ibn-La'Ahad, the Animus, and a story that moved between a contemporary world and the Third Crusade. Parkour and free-running remained important design elements, helping preserve a connection to the movement-focused design associated with Prince of Persia.

The two franchises are therefore related through development history, not through a shared official storyline. Assassin's Creed is not a direct sequel to The Sands of Time. The 2003 Prince of Persia game is the specific inspiration commonly identified for the original concept.