The Ottoman–Safavid War of 1623–1639 was the last of a series of conflicts fought between the Ottoman Empire and Safavid Empire, then the two major powers of Western Asia, over control of Mesopotamia. After initial Persian success in recapturing Baghdad and most of modern Iraq, having lost it for 90 years, the war became a stalemate as the Persians were unable to press further into the Ottoman Empire, and the Ottomans themselves were distracted by wars in Europe and weakened by internal turmoil. Eventually, the Ottomans were able to recover Baghdad, taking heavy losses in the final siege, and the signing of the Treaty of Zuhab ended the war in an Ottoman victory. Roughly speaking, the treaty restored the borders of 1555, with the Safavids keeping Dagestan, eastern Georgia, Eastern Armenia, and the present-day Azerbaijan Republic, while western Georgia and Western Armenia decisively came under Ottoman rule. The eastern part of Samtskhe (Meskheti) was irrevocably lost to the Ottomans as well as Mesopotamia. Although parts of Mesopotamia were briefly retaken by the Iranians later on in history, notably during the reigns of Nader Shah (1736–1747) and Karim Khan Zand (1751–1779), it remained thenceforth in Ottoman hands until the aftermath of World War I.