Abdur Rahman fell in love with Qattama, and proposed marriage to her.

Abdur Rahman fell in love with Qattama, and proposed marriage to her. She told him that the price of her hand was the head of Ali ibn Abi Talib. This only strengthened Abdur Rahman in his resolution. He promised his inamorata the moon if she asked for it, but she said that nothing was of interest to her if she could not get the head of Ali ibn Abi Talib! Abdur Rahman bin Muljam carefully worked out his plans to kill Ali.

A few other trusted Kharjis also volunteered their services to him, and together they rehearsed the assassination. Abdur Rahman bin Muljam took one extra precaution – he put his sword in deadly poison, and let it soak in it for three days. On the morning of the 19th of Ramadan of the year 40 A.H., Ali came into the Great Mosque of Kufa, and called Adhan (the call to prayer). He took his place in the alcove, and moments later, the worshippers began to arrive.

They stood behind him in serried ranks, and the prayer began. Standing in the front row, with other worshippers, were Abdur Rahman bin Muljam and his confederates. They were watching Ali's movements. In the folds of their cloaks, they were carrying swords burnished to a high sheen, and soaked in poison. Just when Ali touched the ground with his forehead for sajda, Abdur Rahman bin Muljam stepped out of his row, and crept into the alcove.

And just when Ali lifted his head from the ground, ibn Muljam struck the fatal blow at his forehead with such deadly force that it split open. Blood squirted from Ali's forehead in several jets, and he exclaimed: “By the Lord of the Kaaba, I am successful!” The members of the congregation realized what had happened, and as soon as they concluded the prayer, they surrounded him. His sons, Hasan and Husain, carried him to his house.

A physician came, and tried to dress the ghastly wound but could not stop the bleeding. The blow of the sword was fatal anyway, but the poison from its blade was also spreading rapidly in his body. The Arab historians say that it was the second time that Ali was wounded in the forehead, the first time being when, in the battle of the Trench fought in 627, the sword of Amr bin Abd Wudd cut through his shield and helmet, and struck it. His forehead still bore the scar left by the sword of Amr.

This is the account left by the Arab historians of the assassination of Ali, and it has been accepted as authentic by the vast majority of the Muslims.