Ctesiphon , ruined ancient city, 20 mi (32 km) SE of Baghdad, Iraq, on the left bank of
the Tigris opposite Seleucia and at the mouth of the Diyala River. After
129 B.C. it was the winter residence of the Parthian kings. Ctesiphon grew rapidly and
was of renowned splendor. The Romans captured it in warring against
Parthia. It became the capital of the Sassanids in c.224 and a center
of Nestorian Christianity. In 637 it was taken and plundered by the
Arabs who renamed it, along with Seleucia, al Madain; it was abandoned
by them when Baghdad became the capital of the Abbasids. It is now a
suburban part of Baghdad
