The Old Man of the Mountain Latin : Vetulus de Montanis), [1] is the expression used by Marco Polo in a passage from Book of the Marvels of the World , to indicate Hassan-i- sabbah, the grand master of the Order of Assassins which was based in Alamut Castle. It later became a common name used by the Crusaders. [2]
Subsequently, this nickname was given to various Isma'ili successors of Hassan, in Syria, particularly, [3] for example Rashid al-Din Sinan, the da'i (missionary) [4] and a leader of the Syrian branch of the Nizari Isma'ili state. [5]