Rashid al-Din
Rashid al-Din Sinan ( "Rashīd ad-Dīn Sinān"), also known as the Old Man of the Mountain ( "Shaykh al-Jabal", ), was a "da'i" (missionary) and a leader of the Syrian branch of the Nizari Isma'ili state (the Assassins), and a figure in the history of the Crusades.