prominently in the history of the Crusades. They had many mountain strongholds, but all were under the control of the Sheikh or “Old Man of the Mountain,” as the Crusaders and Marco Polo called him, at Alamut. These Sheikhs or Grand Masters of the order continued for eight generations, until Alamut was captured by the Mongols in 618 A.H. (= 1221 A.D.), and the last was put to death. As the order grew it spread into Syria, and it was the Syrian branch with which the Crusaders from Europe came most into contact. In this order we find the old system of successive grades of initiation. The _Lasiqs_, or “adherents,” had but little knowledge of the real doctrines of the sect, and attached to them were the _Fida`is_ or “self-devoted,” bound to blind obedience and ready to execute vengeance at the bidding of their superiors; these were the men to whom the Crusaders especially applied the term _Assassins_, that is _Hashishin_ or “users of hashish,” referring to the hashish or Indian hemp which they commonly used as a means of exaltation. Above these were the _Rafiqs_ or “companions,” and above these was an ordered hierarchy of _da`is_ or missionaries, Chief Missionaries (_da`i i-Kabir_), and Supreme Missionary (_da`i d-Du`at_). In the eyes of outsiders the whole sect had a sinister appearance; the crimes of the Fida`is, usually committed under striking and dramatic circumstances, and the reputed heresies of the superior grades were sufficient to secure this, and the general dread with which they were regarded was increased by incidents which showed that they had spies and sympathizers in all directions. The superior grades, however, were true heirs of the old Isma`ilian principles and ardent students of philosophy and science. When the Mongols under Hulagu seized Alamut in 654 (= A.D. 1256) they found an extensive library and an observatory with a collection of valuable astronomical instruments. The Mongol capture meant the downfall of the Assassins, although the Syrian branch still continued in humbler fashion, and the sect has adherents even at the present day. Scattered relics survive also in central Asia, in Persia, and in India; the Agha Khan is a lineal descendant of Ruknu d-Din Khurshah, the last Sheikh at Alamut.