To this the Caliph replied: “I have grasped the meaning of thy letter; but thy position is different from that of the bad Vezīrs of the Sāsānide kings, ... a humble and faithful servant like thyself has nothing to fear during a state of peace. Although the conditions hinted at towards the close of thy letter do not bespeak an entire submission, thou wilt doubtless return with the bearer of this letter. I pray God that He may give thee strength to withstand the enticements of Satan, who hopes to frustrate thy good intentions, and opens for thee the gate which leads to destruction.” Abū Muslim rejoined in the following remarkable letter: “I had a guide closely connected with the house of the Prophet whose business it was to instruct me in the teachings and duties prescribed by God. From him I had hoped to learn the sciences, but he led me into ignorance and error by means of the Koran itself, which, from love of worldly things, he misinterpreted. He ordered me, in God’s name, to draw the sword, to banish feelings of pity from my heart, to accept no excuses from my enemies, and to pardon no offence. I did everything to pave his way to dominion. Nothing now remains for me but to entreat God to pardon me for the sins I have committed.” Having despatched this letter, Abū Muslim set out for Khorāsān, but in the meanwhile El-Mansūr wrote privately to Abū Dā´ūd Khālid, whom Abū Muslim had left as his lieutenant in Khorāsān, appointing him to the governorship. He further pointed out that the army of Khorāsān had obeyed Abū Muslim because he had been fighting for the `Abbāsids; that he was now in open revolt, and ought to be put to death at the first opportunity. Abū Dā´ūd communicated this letter to the army and chiefs of Khorāsān, who at once recognised him as governor. He then sent news of this momentous occurrence to Abū Muslim, who, seeing that he could no longer count on the attachment of the Khorāsānīs, and deceived by the false assurances of his former friends, consented to wait upon the Caliph at Madā´in. On arriving there he was basely murdered at his master’s instigation by five hired assassins, A.H. 137 (754). Abū Muslim was barely thirty-five years of age when he met his fall. It was certainly deserved, for, according to computations of Arabian historians, he was responsible for the slaughter of no less than 600,000 human beings. But though the monster richly merited punishment, his master, on whom he had bestowed the Empire of the East, should have been the last to inflict it; and the treachery with which Abū Muslim’s fate was compassed is an additional stain on El-Mansūr’s memory. CHAPTER XII THE CALIPHATES OF EL-MANSŪR, EL-HĀDI, AND HĀRŪN ER-RASHĪD