Note: Ancient city located on the left (northeast) bank of the Tigris River about 20 miles (32 km) southeast of modern Baghdad, in east-central Iraq. It was the chief city of Seleucid Empire; winter capital of Parthia after 129 BCE; briefly captured by Romans 115 CE; plundered by Arabs 637; fell into decay when Baghdad was founded; Turks defeated British here 1915. The site is famous for the remains of a gigantic vaulted hall, the Ţāq Kisrá, featuring one of the largest single-span brick arches in the world. It is traditionally regarded as the palace of the Sasanian king Khosrow I (reigned 531-579 CE), although Shapur I (reigned 241-272 CE) also undertook work on the site. Other ruins at the site were used as quarries for materials for the building of Baghdad.