Al-'Atrush appeared on the seene of Tabaristan (Mazandaran) in the year 301/913-14, and
drove away the 'Abbasids, called "the Black robed people, from there. He was a gifted man
with great intelligenee,scholarship, knowledge and conviction of faith. He lived for a long
time among the Daylamites, who were Zoroastrians, and some even pagans, living in
complete darkness. The people of Gilan also lived in the same conditions. Al-Nasir al-Kabir
invited them to worship the One God, and they embraced Islam accepting his call. In those
days the Muslims reached Qazwin and the adjoinmg areas. Al Nasir al Kabir built a mosque
in Daylarn.