Capture of Baghdad ( 1638 ) Capture of Baghdad refers to the second conquest of the city by the Ottoman Empire . Background . Baghdad ( capital of modern Iraq ) , once the capital of Arab Abbasid Caliphate , was one of the most important cities of the Muslim World . In the second half of the Medieval age , Turkic rulers ( Seljuks , Kara Koyunlu , Ak Koyunlu ) as well as others always tried to control this prestigious city . In 1534 , Ottoman sultan Suleyman I ( also known as " Suleyman the Magnificent " ) captured the city without any serious combat . However 90 years later it was captured by Abbas I of Persia . Attempts of several Ottoman commanders ( ) to retake the city following 1624 , were fruitless . According to a legend only the sultans could capture the city . Murat was seen as a warrior hero and thus it seemed as his duty to campaign and regain Baghdad . He had been victorious against the Druze rebels a decade earlier and won a great victory at the Siege of Yerevan in 1635 . In 1638 Ottoman Sultan Murat IV ( five generation younger than Suleyman I ) decided to recapture the city . According to the eyewitness account of Zarain Agha the Ottoman mobilization for the siege of Baghdad was 108 , 589 men composed of 35 , 000 infantry in part Janissaries , and 73 , 589 cavalry . The siege . The birds ' flight distance between Istanbul and Baghdad is about . According to historian Joseph von Hammer the Ottoman army covered this distance in 197 days with 110 staging stations in between . The siege began on 15 November 1638 . The Safavids had increased the garrison size of the city by around 4 - 5 times . There were four main gates of the city , the North Gate , " Azamiye " or " Imam - i Azam " , ( of Abū Ḥanīfa ) , the South Gate " Karanlık Kapu " ( dark ) , " Ak " ( white ) and " Köprü " ( bridge ) gates . The Ottoman observer Ziyaeddin Ibrahim Nuri described the city ' s fortifications as follows : the city walls were 25 meters tall and between 10 and 7 meters wide , reinforced by earthen ramparts to withstand artillery bombardment and protected by a wide and deep moat . The city walls featured 114 towers between the North and South Gate , and another 94 towers that ran parallel to the Tigris . The Safavid commander , Bektaş Khan , had made extensive repairs to the fortifications . Two Pashas were deployed against the first two gates . But the Grand Vizier Tayyar Mehmet Pasha noticed that these two gates were very well fortified . So he chose to attack on the third ( Ak ) gate which seemed less fortified . During the siege the Safavids made sallies of around 6 , 000 men at a time , this was followed by a retreat into the city and a fresh 6 , 000 to attack . These types of attacks greatly increased the casualties of the Ottomans . The siege continued for 40 days . Towards the end , impatient Murat urged the Grand Vizier for a general attack . The attack was successful and the city was captured on 25 December 1638 ( on the 116th anniversary of the capture of Rhodes by Suleyman I ) . But during the final clashes , the Grand Vizier was shot down . Aftermath . Although the defenders were given free passage to Persia , some resumed fighting after the capture of the city around Karanlık gate . The human loss during the after - capture fighting was severe . Nevertheless soon after the capture , the new Grand Vizier Kemankeş Mustafa Pasha and the Persian representative Saruhan began peace talks and on 17 May 1639 the treaty of Zuhab was signed , which became an important historical treaty . By this treaty the modern Turkey - Iran and Iraq - Iran frontier lines were drawn . Although there were some other wars after the treaty of Zuhab , the treaties following the wars were merely the ratification of the treaty of Zuhab . Trivia . During the Baghdad campaign Murat lost two of his Grand Viziers . The first was Bayram Pasha on 17 August 1638 , who died on the way to Baghdad and the second was Mehmet Tayyar who died on 24 December 1638 . Tayyar Mehmet was also the third Ottoman Grand Vizier who died on the battle field ( the first two being Hadim Ali Pasha in 1511 and Hadim Sinan Pasha in 1517 ) . After this victory Murat had two magnificent kiosks built in the Topkapi gardens , one for his victory at Yerevan and the other for his victory at Baghdad .