In 1191, the Assassins Altaïr Ibn-La'Ahad, Malik Al-Sayf, and Kadar Al-Sayf were sent by Rashid ad-Din Sinan to retrieve and secure the Apple of Eden. The Assassins found Robert de Sable and four of his men in the vault, about to reach the Piece of Eden. Robert deflected Altaïr's attempt on his life and told the Assassin to deliver a cryptic warning, before hurling Altaïr through a support beam, and cutting him off from the chamber and his Brothers.
Altaïr quickly realized he could not get back to his brothers, and, believing that the mission had failed, returned to Masyaf to report the events to Al Mualim, leaving Malik and Kadar for dead. However, just after Altaïr had returned to Al Mualim five days later, Malik appeared and revealed that he had managed to retrieve the Piece of Eden, though losing his left arm and his brother in the process.
Months later, Malik returned to the chambers beneath the temple and found Robert's journal, apparently discarded during the struggle to retrieve the Piece of Eden, and discovered Al Mualim's involvement in locating the treasure with the Templars, and his true intentions for the artifact.
- Contrary to other First Civilization temples, the Jerusalem Vault did not feature many remnants of First Civilization technology.
- When looking above the ceiling, one could see light passing through the cracks between the rocks.
- The relief where Altaïr confronts Robert de Sable is modeled after the historical site of the Treasury at Petra, Jordan.