This ruler and his wife are interpreted as the title Constantine and Helena in front of the True Cross in the final miniature of the Syriac Lectionary. This ruler burned a library inside a fortress whose name is derived from the words for “eagle” and “taught” in the Daylami dialect. That campaign by this ruler was recounted by one of the Juvayni brothers. The death of this ruler necessitated the marriage of his son and Maria Palaiologina. The anonymous Templar of Tyre recounts how Hethum I assisted a campaign by this ruler, who later eliminated a religious sect founded by Ḥasan-i (“HUH-sun-ee”) Ṣabbāḥ, nicknamed the “Old Man of the Mountain.” Naṣīr al-Dīn al-Ṭūsī convinced this ruler to establish an observatory at Marāgha. This ruler besieged the fortress of Alamut, destroying the Assassins. This ruler had Caliph al-Mustaṣim trampled to death in a carpet. For 10 points, name this founder of the Ilkhanate. ■END■
ANSWER: Hūlāgū Khan [or Hülegü Khan or Holâku Khân or Qülegü Khan] (The Syriac Lectionary depicts the Ilkhanate, in particular Hūlāgū’s Nestorian wife, Doquz Khatun, as protectors of Levantine Christianity. The fortress of Alamut is named for the words aloh and amukht. The penultimate sentence is about the 1258 Sack of Baghdad.)
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= Average correct buzz position