Cyclopedia of Biblical, Theological and Ecclesiastical Literature
(Ancient of the Mountain) is the name of the prince of the Assassins, or those Israelites of Irak who undertook to assassinate all those whom their chief would pronounce to be his enemies.
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McClintock, John. Strong, James. Entry for 'Sheik al-Gebal'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/s/sheik-al-gebal.html. Harper & Brothers. New York. 1870.