In the month of Jumada al-Akhira of the 193rd year of the Hijra, when Hārūn al-Rashīd passed away in the city of Ṭūs, his son Ṣāliḥ wrote a letter to his brother Muḥammad Amīn b. Zubayda, who had been appointed as the heir apparent (walī al-ʿahd) for the period following their father, informing him of their father's death and offering his condolences. At that time, Muḥammad Amīn was in Baghdad. The servant Rajāʾ delivered this letter to him. Along with the letter, there were also the seal, the whip, and the cloak.
On Thursday, the 14th of Jumada al-Akhira, upon receiving this letter, Muḥammad Amīn left the Palace of Eternity (Qaṣr al-Khuld) and went to the palace of Abū Jaʿfar al-Manṣūr, which was located on the bank of the Tigris in Baghdad and known as the Golden Palace. He led the congregation in prayer, then ascended the pulpit and delivered a sermon to them. He offered condolences to the congregation due to the death of Hārūn al-Rashīd. He made many promises to the people and gave them hopes. The notables of his tribe, the leading members of the Hāshimites, and the emirs presented their pledges of allegiance (bayʿa) to him. Muḥammad Amīn ordered that the soldiers be given two years' worth of salaries.
Then, descending from the pulpit, he ordered his uncle Sulaymān b. Jaʿfar to accept the remaining congregation's pledges of allegiance on his behalf.
When Muḥammad Amīn's affairs were set in order and his situation stabilized, his brother
became jealous of him, and, as we shall explain later, a conflict arose between the two.