Abstract
Nasiruddin al-Tusi lived during the Mongol invasion and was an eyewitness in those events which caused the Islamic world to divide, destroy the Islamic cities during the invasions of the the Mongols.
He lived for a while in the ismaili Shiite state and become close to them.
he became one of the great scholars of that state He served the ismaill state until he fell in the hands of the Mongols in 654AH-1256AD by the Mongol and then moved to the service of the Mongol et leur regne a pu Tusi dopten un statut eleve lorsque Hulagu lui a fait lui obeir enreferences par lui, en raison du degree lui fait secretaire Awqaf Mamelouks saisi par, et a manifeste son desir de la recherch et la lecon,et il a exploite Largent a sa disposition lamidonpar une grande bibliotheque et construit observtoire Maragheh,qui est lune plus eminents de lepoque des Mongols,dans le cadre dun grand groupe de scientifiques dans lensemble du mond musulman pour developer cet obsevatoire.
The objective of the selection of the subject is to identify the character of nasir al-din tusi role in the scientific achievments in the era of the mongols, Thisresearch consists of two topics: the first isrelated to the life of nasir al- din al- tusi and then hisfamily and his death,the second topic was devoted to thecastles sttled by nasir al- din al- Tusi during the reign of ismaili and then the posts that heconducted during theruleof the Mongolsand finally devoted most of his scientific achievements.