Sykes' History of Persia Vol 2 (pdf) - Heritage Institute

EXTINCTION OF THE CALIPHATE 165
treated his sovereign with due respect, but after the
capture of Kerman formed a conspiracy against him.
Jalal-u-Din was aware of the treacherous designs, but in
order to avoid creating
a bad impression upon
his first
return to Persia he ignored the plot,
and after spending
a month at Kerman marched westwards into Pars. There
he was at first treated with cool politeness by the Atabeg
Sad, but afterwards became his son-in-law.
Ghias-u-Din. Upon the retirement of the Mongols
from Northern Persia, a younger brother of Jalal-u-Din,
by name Ghias-u-Din, had obtained possession of Khorasan,
Mazanderan, and Irak. Indolent and voluptuous,
this prince was not the man to restore a half- ruined
country, and the army transferred its allegiance
to his
elder brother, who became ruler of Northern Persia,
Ghias-u-Din perforce submitting.
The Campaign against the Caliph^ A.H. 622 (1225).
After establishing his authority as Shah of Khwarazm,
Jalal-u-Din marched to attack the Caliph Nasir, the
enemy of his father. The campaign opened with the
siege of Shuster, which, however, proved impregnable.
He then marched on Baghdad and drew the Caliph's
army into an ambush, whereby he gained a decisive
victory, pursuing his defeated enemy to the gates of the
capital.
He did not attempt to take Baghdad, but
marched north and invaded and occupied Azerbaijan.
Never content to organize
the fruits of his brilliant
victories, Jalal-u-Din had no sooner won Tabriz than
he invaded Georgia, and in two campaigns captured
Tiflis, in A.H. 623 (1226). His next exploit was to
the follow-
extirpate a tribe of raiding Turkoman, and in
ing year he ravaged the Ismaili territories and also beat a
Mongol force at Damghan,
to the east of Rei.
The Battle ofIsfahan, A.H. 625 (1228).
The Mongols
after this defeat appeared in greater force, and pursued a
Persian corps of observation to Isfahan, which was the
Sultan's headquarters.
The Mongol army, composed
of five divisions, prepared to besiege the city, but the
Sultan marched out, determined to fight
in the open.
Although deserted by Ghias-u-Din on the battlefield, this