Why Ma'mun invited Iman Reza (A.S)
After the death of Harun (b, 766 A.D., r. 786-809 A.D.) in 193 A.H./ 809 A.D., Ma'mun fell into conflict with his brother Amin (b 787 A.D., r. 809-813 A.D.), which led to bloody wars and finally the assassination of Amin in 813 A.D./ 198 A.H., after which Ma'mun became caliph.
The Umayyad and the Abbasid caliphs were afraid of the Holy Imams (A.S.), who were publicly recognized as the true and worthy successors of the Messenger of Allah (S.A.W.). The Holy Imams (A.S.), were therefore constantly persecuted and tortured by the ruling caliphs of the time.
