By: Mir M.Hosseini
Ostadsis started his uprising against the Caliph rule to avenge Abu Muslim's murder. Although he did not really like Abu Muslim; because the Behafarid uprising was suppressed by the very Abu Muslim. Ostadsis uprising was indeed the continuation of Behafarid uprising and they shared the same ideology based on a combination of Mazdakism and Islam. However, Abu Muslim was a popular person who staged the first successful Iranian revolt against the Caliph rule, and using his name could create more support.
Most of Ostadsis followers were from Sistan and Khorasan. A large group of Behafarid's followers who had accepted Islam after their leader's death joined this uprising. Another group of non-Arab Muslims who were fed up with a certain kind of tax called Jaziyah also joined Ostadsis. The roots of these revolts against Abbasi Caliphs were economic hardship due to unfair taxes which differed from the revolts against Omavi rule which were caused by racial discrimination.
Some of elite Iranian families had been serving in the Abbasi court made matters more complicated. Ostadsis asked his followers to stop cooperating with those who served the Abbasi Caliph. He soon gained hundreds of thousands of supporters from Sistan to Herat. Soon after the news reached Mansour, the Abbasi Caliph, a great army was dispatched to the region. Due to lack of experience and military training, Ostadsis was defeated with heavy loss on both sides and had to retreat. During cease-fire negotiations, Ostadsis and his family were tricked and they were arrested and all their men were later executed.
After this event, several other uprisings started all over Iran. In a political move to please Iranians, Mansour ordered celebrating Norooz and Mehregan at the royal court. According to some accounts, Mansour's son Mehdi married Kheizaran, a daughter of Ostadsis who later gave birth to Harunolrashid. Although some historians discredit this story.