Philippe Villiers de l'Isle-Adam (1464 – 21 August 1534) was the Grand Master of the Knights Hospitalier from 1521 to his death.
By 1511, the Hospitaliers on Rhodes were aware that it would only be a matter of time before the Ottoman Empire attempted to take the island. Thus, l'Isle-Adam began selling off their library to customers such as Sofia Sartor. The Assassin Mentor Ezio Auditore da Firenze knew from his reputation that l'Isle-Adam was a brave man.
In 1522, the Ottoman Sultan Suleiman I besieged the Hospitalier fortress on Rhodes for six months. Under l'Isle-Adam, the Hospitaliers resisted the siege, and negotiated the capitulation and departure of the knights in 1523.
- In the Revelations novel, Ezio refers to l'Isle-Adam as the Grand Master of the Hospitaliers, despite the latter only reaching that position in 1521, ten years after the events of the novel.