In Khurasan, the work of the Da'wa on behalf of Imam Mahdi was carried out by da'is like Shi'rani, Ghiyath and al-Amir Husayn b. Ali al-Marwazi. Their policy was to get close to the chiefs and rulers of the place as well as their important civil and military officials, and with the official support or connivance, to propagate the Ismaili madhhab among the people. Abu abd Allah Muhammad b. Ahmad an-Nasafi (who is also described by Na'sir-i-Khusr'aw as 'Da'i Abul-Hasan an-Nakhshabi) followed the same policy of his master Da'i Marwazi and of his other predecessors. His success was phenomenal.

It is possible that Da'i Nasafi was born in Bardhaa (in, Southern Caucasus) for which he was called, al-Bardhi, but later became known as, an-Nasafi or an-Nakhshabi, the scene of his activities. He started his work in Khurasan but later crossed the Oxus and went to Bukhara, at that time the capital-of the Samanid Dynasty. He had great success in converting many people of importance, even in the court , of the Samanid ruler Nasr b. Ahmad. Through them he was introduced to the ruler, who it is said accepted Ismailism. Due to this circumstance, his relations with Baghdad were strained. It is said that Nasr b. Ahmad gave allegiance to Imam Mahdi and paid to him an annual tribute of 199 thousand dinars. This was evidence enough of his conversion to Ismailism. Da'i Nasafi took advantage of such favourable conditions and made Ismailism a commonly accepted Madhhab in Central Asia. Da'i Nasafi thus became the most powerful personality in Transoxiana. And this led to jealousy and intrigue against him by the courtiers of Nasr. b. Ahmad.

Ibn Nadim says that in the latter part of his reign, Nasr showed some wavering, but he soon died. His son Nuh, however, who had been brought up under the guidance of Sunni theologians reversed the policy. He made Da'i Nasafi enter into a controversy with these theologians and later got them to pass a verdict of heresy against him. Making this as an excuse, he ordered Da'i Nasafi's execution, arrested and beheaded the officers of his father, who had accepted Ismailism and carried out a merciless general massacre of the Ismailis in Transoxiana and Khurasan. This is known at the "Great Calamity" of the Ismaili community and it is this that the Great Da'i Nasifi sacrificed himself and became a martyr. This happened in 331 H. After this the Ismaili 'Da'wa in these territories remained low, till it was revived by Nasir-i-Khusraw and Hasan bin Sabbah a century, and a half later.

We have seen what great political contribution Da'i Nasafi made to the Imamate of Imam Mahdi. But his mission was not confined at that. He also wrote great works which although they have not survived, have nevertheless made a lasting influence on the doctrine and ideology of Ismailism as enunciated by later writers. Most renowned work of his is Kitab al Mahsul, extensive extracts from which are copied in the book of Da'i Kirmani, called Kitab ar Rivad. It is purely on philosophical matters and is marked for its free thinking speculations. We have noted above that Dai Nasafis contemporary Da'i Abu Hatim ar-Razi was commissioned by Imam Mahdi to write a correction of this work, in so far as it contained some deviations from the Ismaili orthodoxy. This does not mean that Kitab al Mahsul lost its reliability. On the contrary the great Da'i Kirmani gives much importance and credit to this work. It only demonstrates the vastness and flexibility of Ismaili doctrine. Other works of the Da'i as mentioned by Ibn-an-Nadim are Kitab an-Unwan ad-din, kitab usul ash-shara and kitab an-dawat al Munjiva. None of these has survived.