What was Assassin's Creed originally planned as a spin-off of?

Assassin's Creed was originally planned as a spin-off of Prince of Persia. The project developed from ideas for a Prince of Persia game centered on a younger, stealth-focused character.

Ubisoft Montreal's work eventually moved away from the established Prince of Persia framework. The team built a new setting around Assassins, Templars, historical cities, and the Animus, creating a separate intellectual property.

The finished game retained design ideas associated with the earlier series, including acrobatic movement, rooftop traversal, and a strong historical-fantasy atmosphere. Its success allowed Assassin's Creed to become its own long-running franchise.

This origin story is why the two series are sometimes discussed together, but they are separate properties. Prince of Persia continued independently, including later games such as The Lost Crown.