Excerpts from The Ismailis: Their History and Doctrines, by Farhad Daftary, at p 411
“But the Nizaris of Quhistan never recovered from the Mongol onslaught, which left all of Khurasan in ruins. They survived clandestinely in villages around Birjand ….
…Nizari Quhistani was born in Birjand in 645/1247-1248 into a land-owning Ismaili family.
Nizari Quhistani served for a while a the court and chancery of … the governor of Quhistan.
…[Nizari Quhistani] died destitute in 720/1320 in his native Birjand.
Belonging to a family whose Ismaili affiliation was a known fact before the arrival of the Mongols, Nizari may have found it rather difficult to dissimulate his true religious identity in later life.”
Ismailimail 