Al Mamoun placed his two sons under the tuition of Al Farra, so that they might be instructed in grammar. One day Al Farra rose to leave the house, and the two young princes hastened to bring his shoes. They struggled between themselves for the honor of offering them to him, and they finally agreed that each of them should present him with one slipper. As Al Mamoun had secret agents who informed him of everything that passed, he learned what had taken place, and caused Al Farra to be brought before him.
When he entered, the Caliph said to him: "Who is the most honored of men?" Al Farra answered: "I know not any one more honored than the Commander of the Faithful." "Nay," replied Al Mamoun, "it is he who arose to go out, and the two designated successors of the Commander of the Faithful contended for the honor of presenting him his slippers, and at length agreed that each of them should offer him one."
Al Farra answered: "Commander of the Faithful, I should have prevented them from doing so had I not been apprehensive of discouraging their minds in the pursuit of that excellence to which they ardently aspire. We know by tradition that Ibn Abbas held the stirrups of Hasan and Husain, when they were getting on horseback after paying him a visit. One of those who were present said to him: 'How is it that you hold the stirrups of these striplings, you who are their elder?' To which he replied: 'Ignorant man! No one can appreciate the merit of people of merit except a man of merit.'"
Al Mamoun then said to him: "Had you prevented them, I should have declared you in fault. That which they have done is no debasement of their dignity; on the contrary, it exalts their merit. No man, though great in rank, can be dispensed from three obligations: he must respect his sovereign, venerate his father, and honor his preceptor. As a reward for their conduct, I bestow upon them twenty thousand dinars ($50,000), and on you for the good education you give them, ten thousand dirhems" ($2,500).
When Al Mamoun was still in Khorassan, a revolt was raised against him in Bagdad by his uncle, Ibrahim, the son of Mahdi. This prince had great talent as a singer, and was a skilful performer on musical instruments. Being of a dark complexion, which he inherited from his mother, Shikla, who was a negress, and of a large frame of body, he received the name of At-Tinnin (the Dragon). He was proclaimed Caliph at Bagdad during the absence of Al Mamoun. The cause which led the people to renounce Al Mamoun and choose Ibrahim was that the former had chosen as his successor one of the descendants of Ali, and in doing so had ordered the public to cease wearing black, which was the distinctive color of the Abbassides, the reigning family, and to put on green, the color of the family of Ali and their partizans.
On Mamoun's entry into Bagdad, Ibrahim fled disguised as a woman. He was, however, detected and arrested by one of the negro police. When he was before Al Mamoun, who addressed him in ironic terms, he replied: "Prince of the believers, my crime gives you the right of retaliation, but 'forgiveness is near neighbor to piety.'[9] God has placed you above all those who are generous, as he has placed me above all criminals in the magnitude of my crime. If you punish me you will be just; if you pardon me you will be great." "Then I pardon you," said Mamoun, and prostrated himself in prayer.
He commanded, however, that Ibrahim should continue to wear the burqa, or long female veil in which he had fled, so that people might see in what disguise he had been arrested; he ordered also that he should be exposed to view in the palace courtyard; then he committed him to police supervision, and finally, after some days of detention, set him free.
The following anecdote was related by Ibrahim regarding the time when he was in hiding with a price set on his head: "I went out one day at the hour of noon without knowing whither I was going. I found myself in a narrow street, which ended in a cul-de-sac, and noticed a negro standing in front of the door of a house. I went straight to him, and asked if he could afford me shelter for a short time. He consented, and bade me enter. The hall was adorned with mats and leather cushions. Then he left me alone, closed the door, and departed. A suspicion flashed across my mind; this man knew that a price was set on my head, and had gone to denounce me.
"While I was revolving these gloomy thoughts, he returned with a servant bearing a tray loaded with victuals. 'May my life be a sacrifice for you,' he said. 'I am a barber, and therefore I have not touched any of these things with my hand; do me the honor to partake of them.' Hunger pressed me; I rose and obeyed. 'What about some wine?' he asked. 'I do not detest it,' I replied. He brought some, and then said again: 'May my life be your ransom! Will you allow me to sit near you and drink to your health?' I consented. After having emptied three cups, he opened a cupboard and took out a lute. 'Sir,' he said, 'it does not behoove a man of my low degree to beg you to sing, but your kindness prompts me to do so; if you deign to consent it will be a great honor for your slave.'
"'How do you know that I am a good singer?' I asked him. 'By Allah!' he answered, with an air of astonishment, 'your reputation is too great for me not to know it: you are Ibrahim, the son of Mahdi, and a reward of a hundred thousand dirhems is promised by Al Mamoun to the man who will find you.' At these words I took the lute, and was about to commence, when he added: 'Sir, would you be so kind as first to sing the piece which I shall choose?' When I consented he chose three airs in which I had no rival. Then I said to him: 'You know me, I admit; but where did you learn to know these three airs?' 'I have been,' he answered, 'in the service of Ishak, son of Ibrahim Mausili,[10] and I have often heard him speak of the great singers and the airs in which they excelled; but who could have guessed that I would hear you myself and in my own house?'