When Haroun al Rashid died he left the empire to his sons Emin and Mamoun, giving the former Irak and Syria, and the latter Khorassan and Persia. Emin had the title of Caliph, to which Mamoun was to succeed. War broke out between the brothers; Emin fled from Bagdad, but was captured and slain, and his head sent to Mamoun in Khorassan, who wept at the sight of it. He had, however, previously, when his general Tahir sent to him requesting to know what to do with Emin in case he caught him, sent to the general a shirt with no opening in it for the head. By this Tahir knew that he wished Emin to be put to death, and acted accordingly. The Caliph, however, bore a grudge against Tahir for the death of his brother, as was shown by the following circumstance: Tahir went one day to ask some favor from Al Mamoun; the latter granted it, and then wept till his eyes were bathed in tears. "Commander of the Faithful," said Tahir, "why do you weep? May God never cause you to shed a tear! The universe obeys you, and you have obtained your utmost wishes." "I weep not," replied the Caliph, "from any humiliation which may have befallen me, neither do I weep from grief, but my mind is never free from cares." These words gave great uneasiness to Tahir, and, on retiring, he said to Husain, the eunuch who waited at the door of the Caliph's private apartment: "I wish you to ask the Commander of the Faithful why he wept on seeing me." On reaching home Tahir sent Husain one hundred thousand dirhems. Some time afterward, when Al Mamoun was alone and in a good humor, Husain said to him: "Why did you weep when Tahir came to see you?" "What is that to you?" replied the Prince. "It made me sad to see you weep," answered the eunuch. "I shall tell you the reason," the Caliph said; "but if you ever allow it to pass your lips, I shall have your head taken off." "O my master," the eunuch replied, "did I ever disclose any of your secrets?" "I was thinking of my brother Emin," said the Caliph, "and of the misfortune which befell him, so that I was nearly choked with weeping; but Tahir shall not escape me! I shall make him feel what he will not like." Husain related this to Tahir, who immediately rode off to the Vizier Abi Khalid, and said to him: "I am not parsimonious in my gratitude, and a service rendered to me is never lost; contrive to have me removed away from Al Mamoun." "I shall," replied Abi Khalid. "Come to me to-morrow morning." He then rode off to Al Mamoun, and said: "I was not able to sleep last night." "Why so?" asked the Caliph. "Because you have entrusted Ghassan with the government of Khorassan, and his friends are very few, and I fear that ruin awaits him." "And whom do you think a proper person for it?" said Al Mamoun. "Tahir," replied Abi Khalid. "He is ambitious," observed the Caliph. "I will answer for his conduct," said the other.