Adad was a laborer during the early 16th century, in the employment of the Byzantine Templars.
Around 1510, Adad was hired by the Byzantines to work for them in Masyaf. Not knowing what he was looking for exactly, Adad spent an entire year locating and making his way to the antechamber that held the door to Altaïr's library.
Upon reaching it, he attempted to break through the door. However, after three months, he was still unable to make even the slightest dent in the stone, which seemed harder than steel to him.
In March 1511, Adad was discovered by the Assassin Ezio Auditore, who was also trying to enter the library. The Assassin killed the guards overseeing Adad's work, and then asked the worker for information.
Ezio told him to leave Masyaf, and start working with honest people, to which Adad replied that he would love to, but feared retaliation from the Templars. To circumvent this, the Assassin gave him some money, and escorted him to safety.