Cem

Prince Cem (22 December 1459 – 25 February 1495) was a pretender to the Ottoman throne, and a son of Mehmed II and brother of Bayezid II.

After his brother became Sultan, Cem was placed under house arrest in Italy. He secretly became a close friend of Rodrigo Borgia, or Pope Alexander VI, and became closely allied with the Borgia family. Rodrigo intended to use Cem's ambition to conquer Constantinople for himself. However, the Assassin Brotherhood, realizing this plan, assassinated Cem in Capua in 1495.

Source

 * Assassin's Creed: Revelations novel