Old Man of the Mountain, a name given to Hassan ben Sabbah, the founder in the 11th century and his successors of a formidable Mohammedan dynasty in Syria, whose residence was in the mountain fastnesses of the country, and whose following was known by the name of Assassins (q.v.).
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
Old Catholics * Old Man of the Sea