"We knew you'd come. Robert needed to be sure he'd have time to get away."
―Maria talking about her act as a decoy to Altaïr in AC1― 1191.

Following the deaths of eight powerful Templars in 1191 at the hands of Assassin Altaïr Ibn-La'Ahad, Robert correctly reasoned that he was next on the Assassin's list. Not one to be defeated, Robert publicly announced his intention to attend the funeral of the late Regent of Jerusalem, Majd Addin, as a show of mutual cooperation and respect between Muslims and Crusaders. Privately however, the Grand Master knew that this would be a chance too desirable for the Assassin to pass up. Thus, Maria was left to take Robert's place at the funeral, posing as a decoy in wait for Altaïr.

As expected, the Assassin appeared during the funeral procession, and Maria carefully examined the gathering of guests to spot him. She signaled the funeral proctor to Altaïr's presence, and a great number of Templars were ordered to seize him.

Surprised but composed, Altaïr overpowered the soldiers, pinned Maria to the ground and removed her helm. Discovering her to not be Robert, Altaïr was greatly shocked that it was a woman he had fought, and questioned it as sorcery. Maria corrected him by saying that it was not, and revealed that she was in Robert's place as a distraction, mentioning that the success of Altaïr's Brotherhood in taking the Templar treasure and eradicating her comrades had not gone unnoticed.

Maria continued, revealing that Robert had headed to Arsuf to propose a truce between the Saracen and Crusader armies, in order to besiege the Assassin fortress of Masyaf. As the Templars killed by Altaïr came from both sides of the conflict, the Assassins were now their common enemy.

Though Maria thought she would be the ninth of the Templars to die at the Assassin's hand, Altaïr rebutted her, sparing her life but warning her not to follow him. Maria replied haughtily that she did not need to, and that it was futile for him to try to stop Robert.

"Hello everyone, this time... I bring you another Skin. It's about Maria Thorpe, yes. That decoy Templar that Altair almost killed, and soon... by fate and adventures, they would be husband and wife. Which if you didn't know, yes, brothers. Altair was a father of 2 children. His 2 children were: Darim and Sef, 2 legendary assassins who died. That's right, I don't remember who died first, Sef? Or Darim? It doesn't matter (And yes, I have read the legendary book Assassin's Creed: The Secret Crusade. And what a story! It's incredible. I recommend it to you to understand the story of Altair and his sons, as well as the characters of Altair's father, Al-Mualim, etc.) whatever... join Maria and stop the evils of this world. Along with Altair. There are 2 Skins, one without the Templar helmet. And the other with the helmet on, whatever friends... Enjoy it!" -More legendary Skins are coming, I haven't seen them anywhere! So? Don't fall asleep on me!-