Qasr-e Shirin

Qasr-e Shirin lies beside the Alvand River near the western approaches to the Iranian plateau. Its name recalls Shirin, the celebrated beloved of the Sasanian king Khosrow II, to whom the construction of a palace here is attributed. Another Sasanian monument, the four-arched Chahar Qapu, probably served as a fire temple. The remains stand where the mountains descend towards the plains of Mesopotamia.

In 1639 the Ottoman and Safavid states concluded the peace of Qasr-e Shirin after years of war. The agreement confirmed Ottoman possession of Baghdad and much of Mesopotamia and largely reaffirmed the earlier frontier laid down at Amasya. The settlement helped end a prolonged struggle between the two empires, leaving the town's name attached to a boundary that endured through later changes of government.