During Mutawakkil’s rule, a woman claimed to be Zainab, the daughter of Ali and Fatima and also claimed that because of prayer of Prophet she regains her youth every forty or fifty years. Mutawakkil asked the scholars to refute this claim but no one succeeded; so Fatah Ibne Khakan summoned the grandson of Holy Prophet,Imam Ali al-Naqi(a.s). Imam Ali Naqi (a.s) said: Almighty Allah had made the flesh of the descendants of Prophet unlawful on animals. Sent her to your lion den and the truth will become clear. The courtiers got an idea and told the king why they should not try this first with the Imam himself and they sent the Imam into the cage first. Imam (a.s) agreed to it while Mutawakkil watched the scene from a high spot. The wild beasts placed their heads at the Imam’s feet and he stroked them for sometime. When he came out, his miracle became famous everywhere. Mutawakkil presented expensive gifts to the
Imam and impostor, Zainab was exposed. It also proved that those who falsely claim to be Sayyids are not worth more than this Zainab.
We should know that the law that Imam (a.s) stated is only from the direct descendants of Holy Prophet (s.a.w.a) through Lady Fatima (a.s). After that all are called as descendants of Prophet generally.
Jilaul Uyun, Pg. 293;
Sawaiqul Mohriqa, Pg. 124;
Pg. 461 Damatus Sakiba, Vol. 3, Pg, 145