Ctesiphon was a Sasanian royal city near modern Baghdad and a major western center of Silk Road exchange.
Situated on the Tigris River in Mesopotamia, Ctesiphon served as the principal capital of the Sasanian Empire for much of its history. Its location placed it between Iranian plateau routes, Mesopotamian river transport, Arabia, the Roman world, and Central Asian trade networks.
The city is especially famous for the Taq Kasra, a monumental brick iwan whose surviving vault is one of the largest premodern brick arches. Ctesiphon was a political and commercial center rather than a single roadside stop for caravans.
Arab Muslim forces captured Ctesiphon in 637 during the conquest of the Sasanian Empire. The capital’s political role then declined, although settlement continued in the area. Ctesiphon is sometimes confused with Persepolis, but Persepolis was an Achaemenid ceremonial capital much farther south.