muhammad ibn ja`far ibn muhammad rose up against alma`mun in mecca and alma`mun defeated him. he was an old scholar of hadith so he did not ask him to do more than ascend the pulpit and lie to himself and he did. 
محمد بن جعفر بن محمد قام على المأمون بمكة فظفر به المأمون، وكان شيخا محدثا، فلم يكلفه أكثر من أن يصعد المنبر فيكذب نفسه ففعل. .