The Abbasids took notice of the rapid conversion of the Ismailis in Khorasan, notably Nasr bin Ahmad, and insinuated Nuh bin Nasr (331-343/943-954), the son of Nasr bin Ahmad; against his father and the Ismailis. Nuh bin Nasr dethroned his father and conducted a barbarous massacre of the Ismailis in 331/942, known in the Ismaili history as al-mainat al-uzama (great calamity) in Khorasan and Transoxania. An-Nasafi and his chief associates were also executed in the wild operations at Bukhara in 332/943. For this reason, Nasir Khusaro called him Khwaj-i Shahid and Shaikh al-Shahid. It resulted a setback in Ismaili mission, but was resumed under an-Nasafi's son, Masud, surnamed Dihqan and Abu Yaqub as-Sijistani.