The position of representative of the Imam was held in those times...

The position of representative of the Imam was held in those times, by four personalities, whom the popular bases agreed as to their fear of Allah, piety and integrity. They were: 'Uthman ibn Sa'id al-'Amri; Muhammad ibn 'Uthman ibn Sa'id al-'Amri; Abu'l-Qasim al-Husayn ibn Ruh; and Abu'l-Hasan 'Ali ibn Muhammad as-Samuri. These four individuals assumed the role of representative of the Imam (al-Mahdi) according to the above classification.

So whenever one of them died, the other succeeded him, after being designated by al- Imam al-Mahdi (peace be upon him). The representative of the Imam used to get in touch with the Shi'ahs and submit their questions and…