قلعة ألموت
Shortly after establishing their headquarters at Alamut Castle, the sect captured Lambsar Castle, to be the largest of the Isma'ili fortresses and confirming the Assassins' power in northern Persia. The estimated date of the capture of Lambsar varies between 1096 and 1102. The castle was taken under the command of Kiya Buzurg Ummid, later Sabbah's successor, who remained commandant of the fortress for twenty years. No interactions between the Christian forces of the First Crusade and the Assassins have been noted, with the latter concentrating on the Muslim enemies of the former. Other than a mention of Tancred's 1106 taking of Apamea (see below) in "Gesta Tancredi", Western Europe likely first learned of the Assassins from the chronicles of William of Tyre, "A History of Deeds Done Beyond the Sea," published much later. William coined the phrase "Old Man of the Mountain" to describe the Nizari Isma'ili "da'i" at Alamut.