later lost these territories to the expanding Ottomans following the Peace of Amasya (1555).

In the early 17th century, the Safavids under king (shah) Abbas I (r. 1588-1629) once again regained Shatt al-Arab. Control of the river was at last permanently ceded to the Ottomans with the Treaty of Zuhab in 1639. Control of the waterway was also temporarily