The present article is the first of two articles written by the author to show the misrepresentation of certain historical facts and to refute groundless accusations against the Shi`ah and in particular the role of the great philosopher, theologian, astronomer and mathematician Khawajah Nasir al-Din al-Tusi.
The present article, which appeared in the Persian journal Kayhan-e Andisheh (No. 22), is a study of the allegations regarding the role of Nasir al-Din al-Tusi in the fall of Baghdad and the downfall of the `Abbasid dynasty at the hands of the Mongol conqueror, Hulagu Khan.
The second article is concerned with the role of the Shi'i minister of the Caliph, Ibn `Alqami, and allegations regarding the Shi'ah of Iraq in respect of their role in the fall of the `Abbasid caliphate.
It is hoped that such objective studies will help put an end to inter-sectarian prejudices and contribute to Muslim unity by showing how baseless allegations and indifference to historical facts had led to create an atmosphere of mutual suspicion and hostility amongst Muslims that provided an opportunity to the enemies of Islam and Muslims to divide Muslims for their own advantage.