The movement of Mukhtar and the idea of the Mahdi attached...

The movement of Mukhtar and the idea of the Mahdi attached to the person of Muhammad b. al-Hanafiya, with its extremist and esoteric doctrines, or other ramifications of the Shi'a, are therefore beyond the scope of this study.

It may, however, be pointed out here for future reference that from this time of the confusion in the leadership which followed the death of Husayn, this study has to address itself to two different questions: first, how legitimist Shi'ism maintained its separate identity without being absorbed into the emerging Sunni synthesis; and second, how it maintained its own character distinct from the revolutionary and extremist branches within Shi'ism itself.

To resist the latter form of absorption was indeed more difficult, since extremist and revolutionary ideas are often more appealing than moderate ones. As long as Husayn was alive the Shi'is remained united, considering him the only head and Imam of the House of the Prophet. But his sudden death and the quiescent attitude of his only surviving son 'Ali, more commonly known as Zayn al-'Abidin, left the Shi'a in confusion and created a vacuum in the active leadership of the followers of the .

Thus the period following Husayn's death marks the first conflict over the leadership of the followers of 'Ali, resulting in the division of the Shi'a into various groups. 'Ali Zayn al-'Abidin was the only one of the sons of Husayn whose life was spared during the massacre at Karbala, since he did not take part in the fighting due to illness.

He was at that time twenty-three years old.[^3] After his return from Karbala, Zayn al-'Abidin lived in Medina for most of his life, avoiding any political involvement as much as he could. The tragedy of Karbala left a deep mark on him and it was only too natural that he bore a deep grudge against the Umayyads, holding them responsible for the massacre of his father and all other family members. In spite of this feeling, however, he refrained from expressing any hostile attitude towards them.

As a result, the Umayyads also tried to maintain good relations with him; in particular, Marwan b. al-Hakam and his son 'Abd al-Malik even showed a certain respect and affection for him.[^4] When the Medinese rose against Yazid b.