s victorious march, conquered
Ahwaz, took Wasit and Madain, and pitched his camp near one of the gates
of the capital, where he was rejoined by Harthama. One after the other
the provinces fell away from Amin, and he soon found himself in
possession of Bagdad alone. The city, though blockaded on every side,
made a desperate defence for nearly two years. Ultimately the eastern
part of the city fell into the hands of Tahir, and Amin, deserted by his
followers, was compelled to surrender. He resolved to treat with
Harthama, as he was averse to Tahir; but this step caused his ruin.
Tahir succeeded in intercepting him on his way to Harthama, and
immediately ordered him to be put to death. His head was sent to Mamun
(September 813). It was presented to him by his vizier, Fadl b. Sahl,
surnamed Dhu'l-Riyasatain, or "the man with two governments," because
his master had committed to him both the ministry of war and the general
administration. Mamun hid his joy beneath a feigned display of sorrow.

Amin was only twenty-eight years old. As a ruler he was wholly
incompetent. He hardly comprehended the importance of the affairs with
which he was called upon to deal. He acted invariably on the advice of
those who for the time had his confidence, and occupied himself mainly
with the affairs of his harem, with polo, fishing, wine and music. The
five years of his reign were disastrous to the empire, and in particular
to Bagdad which never entirely recovered its old splendour.

7. _Reign of Mamun._--On the day following the death of Amin Tahir
caused Mamun to be proclaimed at Bagdad, and promised in his name a
general amnesty. The accession of this prince appeared likely to restore
to the empire the order necessary for its prosperity. It was not so,
however. The reign of Mamun--that reign in which art, science and
letters, under the patronage of the caliph, threw so brilliant a
lustre--had a very stormy beginning. Mamun was in no haste to remove to
Bagdad, but continued to reside at Merv. In his gratitude to Fadl b.
Sahl, to whose service he owed his success, he not only chose him as
prime minister of the empire, but also named his brother, Hasan b. Sahl,
governor of Media, Fars, Ahwaz, Arabia and Irak. The two generals to
whom he owed still more were not treated as they deserved. Harthama was
ordered to return to Khorasan; Tahir was made governor of Mesopotamia
and Syria, with the task of subduing Nasr b. Shabath, who with numerous
adh