Ctesiphon

Ctesiphon was an ancient city on the eastern bank of the Tigris, located across from the site of modern-day Baghdad in present-day Iraq. It developed as a major urban center in Mesopotamia and served at various times as the capital or administrative heart of major empires, most notably the Parthian Empire and later the Sassanian Empire. Its strategic position on the Tigris and along east–west trade routes contributed to its wealth and influence, linking the Roman-Byzantine world with the Persian and Indian realms.

Historically, Ctesiphon rose to prominence under Parthian rule and remained a key political and economic center into the Sassanian era, when the city served as a principal royal residence and seat of government for much of the empire. Its architecture and urban layout reflect sophisticated late antique Mesopotamian planning, including a grand palace complex and extensive markets. The city remained important into the early Islamic period, but was gradually eclipsed and ultimately declined after the Arab conquest in the mid-7th century.

Today, the site lies near the town of Salman Pak, with the Arch of Ctesiphon (Taq Kasra) surviving as a prominent example of Sassanian brickwork and one of the most enduring monuments of ancient Persia. The name Ctesiphon appears in Greek and Roman sources, while the local name used during its heyday is not definitively recorded.