years. He was
buried at Mecca. He was a man of rare energy and strength of mind. His
ambition was boundless and no means, however perfidious, were despised
by him. But he was a great statesman and knew how to choose able
officers for all places. He was thrifty and anxious to leave to his son
a full treasury. He seems to have cherished the ideal that this son,
called Mahommed b. Abdallah, after the Prophet, should fulfil the
promises of peace and happiness that had been tendered to the believers,
and therefore to have called him al-Mahdi. For that purpose it was
necessary that he should have the means not only to meet all state
expenses, but also to be bounteous. But from the report of the historian
Haitham b. 'Adi[31] about the last discourse which father and son had
together, we gather that the former had misgivings in regard to the
fulfilment of his wishes.

Khalid b. Barmak took the greatest care of the revenues, but contrived
at the same time to consult his own interests. Mansur discovered this in
the same year in which he died, and threatened him with death unless he
should pay to the treasury three millions of dirhems within three days.
Khalid already had so many friends that the sum was brought together
with the exception of 30,000 dirhems. At that moment tidings came about
a rising in the province of Mosul, and a friend of Khalid said to the
caliph that Khalid was the only man capable of putting it down.
Thereupon Mansur overlooked the deficiency and gave Khalid the
government of Mosul. "And," said a citizen of that town, "we had such an
awe and reverence for Khalid, that he appeased the disorders, almost
without punishing anybody."

3. _Reign of Mahdi._--As soon as Mansur was dead, Rabi', his client and
chamberlain, induced all the princes and generals who accompanied the
caliph, to take the oath of allegiance to his son Mahommed al-Mahdi, who
was then at Bagdad. Isa b. Musa hesitated, but was compelled to give in.
In 776 Mahdi constrained him for a large bribe to renounce his right of
succession in favour of his sons, Musa and Harun. Mansur wrote in his
testament to his son that he had brought together so much money that,
even if no revenue should come in for ten years, it would suffice for
all the wants of the state. Mahdi, therefore, could afford to be
munificent, and in order to make his accession doubly welcome to his
subjects, he began by granting a general amnesty to political prisoners.
Among these wa