After his death in 1221, Imam Jalal al-Din Hasan was succeeded by his son ‘Ala al-Din Muhammad.
Ascending to the throne at only nine years of age, Imam 'Ala al-Din Muhammad continued his father's policy of maintaining close relations with the Abbasid caliph.
Under the leadership of Imam 'Ala al-Din Muhammad, the need for an Imam to constantly guide the community according to the demands of the times was emphasized.
Intellectual life and scholarship flourished under the rule of Imam 'Ala al-Din Muhammad.
The Nizari libraries were invigorated with scholars from across Asia, fleeing from the invading Mongols.
Among these intellectuals, some, including Naṣīr al-Din Tusi, were responsible for important contributions to Ismaili thought towards the end of the Alamut period.
Having written on the topics of astronomy, philosophy, and theology, Tusi's notable contributions to Ismaili thought include Rawdat al-Taslim  (Paradise of Submission), which he composed with Hasan-i Mahmud Katib, and Sayr va Suluk (The Journey), his spiritual autobiography.
Following his two major ethical works, al-Tusi studied under the patronage of the Ismaili Imam at the Alamut library until it capitulated to the Mongols in 1256.
After his death in 1221, Imam Jalal al-Din Hasan was succeeded by his son ‘Ala al-Din Muhammad. Ascending to the throne at only nine years of age, Imam 'Ala al-Din Muhammad continued his father's policy of maintaining close relations with the Abbasid caliph. Under the leadership of Imam 'Ala al-Din Muhammad, the need for an Imam to constantly guide the community according to the demands of the times was emphasized. Intellectual life and scholarship flourished under the rule of Imam 'Ala al-Din Muhammad. The Nizari libraries were invigorated with scholars from across Asia, fleeing from the invading Mongols. Among these intellectuals, some, including Naṣīr al-Din Tusi, were responsible for important contributions to Ismaili thought towards the end of the Alamut period. Having written on the topics of astronomy, philosophy, and theology, Tusi's notable contributions to Ismaili thought include Rawdat al-Taslim  (Paradise of Submission), which he composed with Hasan-i Mahmud Katib, and Sayr va Suluk (The Journey), his spiritual autobiography. Following his two major ethical works, al-Tusi studied under the patronage of the Ismaili Imam at the Alamut library until it capitulated to the Mongols in 1256.
Alamut Castle