Assassin's Creed is a sandbox-style action-adventure video game developed by Ubisoft Montreal and published by Ubisoft. It was released worldwide in November 2007 on the Xbox 360 and PlayStation 3 video game consoles. Alongside the standard retail version, a limited collector's edition was released in North America for PlayStation 3 and Xbox 360. The European limited edition contains the game and a 2-inch (51 mm) Altaïr figure in addition to an art book and a DVD containing several short films. The North American PC version was released on April 8, 2008.

A prequel for this game, titled Assassin's Creed: Altaïr's Chronicles and developed by Gameloft, was released on February 5, 2008 for the Nintendo DS. It was also ported to the Symbian Mobile. A sequel was announced on April 16, 2009. Confirmed by Ubisoft, it is set to be released worldwide Christmas 2009. A new Assassin's Creed PSP game has been announced by Ubisoft with no set release date as of yet. A port of Assassin's Creed: Altaïr's Chronicles has also been released for the iPhone OS on April 23, 2009.

Plot

At the start of the memories, Altaïr is shown attempting to retrieve a "Piece of Eden", a strange artifact, from Solomon's Temple with the help of other assassins, but is stopped by Robert IV de Sablé, a member of the Knights Templar and sworn enemies of the assassins. While retrieving the treasure, Altaïr breaks all three tenets of the Assassin's Creed to attempt to kill de Sablé, but fails. Upon returning to Masyaf, Al Mualim (المعلم, "The Teacher"), leader of the Assassins, demotes Altaïr to an initiate, making him a novice again and giving him another chance to rise through the ranks of the Brotherhood. To this end, Al Mualim assigns Altaïr the task of assassinating nine key figures across the Holy Land in Jerusalem, Acre and Damascus, to attempt to bring peace between the Crusaders and Muslim forces.

Altaïr methodically completes each task, learning that each target is connected to Robert and the Templars and share their mysterious goals. As he completes each of the assassinations, he finds out that the Templars are trying to trick the Muslim and Christian forces to work together and face a common enemy, the assassins, as to bring peace and unity to the world. Altaïr's final target, de Sablé, reveals in his dying words that Al Mualim is himself a member of the Knights Templar, and used Altaïr to kill the other members so he could keep the treasure for himself. Altaïr quickly returns to Masyaf to accost his master. Al Mualim reveals the truth; the Piece of Eden which he had secretly collected from the Temple after Altaïr's transgression, creates illusions, and he denounces religion and other seemingly supernatural events as illusions caused by it. He then states his intention to use the artifact to compel mankind into a brainwashed state and so bring an end to conflict. Altaïr is eventually able to see through deceptions created by the artifact to kill Al Mualim. When Altaïr recovers the artifact, the Piece of Eden activates, showing a holographic view of the world with numerous locations marked across the globe.