Territorial evolution of the Ottoman Empire
Suleiman I ( "Süleymān", ; almost always "Kanuni Sultan Süleyman") (6 November 1494  – 5/6/7 September 1566), was the tenth and longest-reigning Sultan of the Ottoman Empire, from 1520 to his death in 1566. Suleiman became a prominent monarch of 16th century Europe. Suleiman personally led Ottoman armies to conquer the Christian strongholds of Belgrade, Rhodes, and most of Hungary. In 1541 he annexed central Hungary while Transylvania became an Ottoman vassal. However rest of the Kingdom of Hungary including western and northern (Upper) Hungary and Croatia still were Habsburgs possessions. Suleiman also conquered Iraq in his conflict with the Safavid dynasty. Under his rule, the Ottoman fleet dominated the seas from the Mediterranean to the Red Sea and the Persian Gulf.
Safavid occupation of Basra (1697–1701)
Under Suleiman I's successor, Sultan Husayn (1694–1722), Iranian policy in relation to regaining Iraq did not change. According to Professor Rudi Matthee "this is hardly surprising", given that the Safavid army was weak at the time and the Shah himself was famous for his unassertive stance. Matthee does add that there is "great irony in it" given the "religious zeal" associated with Sultan Husayn. Unlike most of his predecessors, Sultan Husayn was a Safavid ruler who actively encouraged pilgrimages to the Shi'ite holy shrines in Iraq; Matthee thus adds that "during his reign Persian pilgrims visited the holy sites in unprecedented numbers". Sultan Husayn was also willing to spend resources of the Safavid state for the upkeep of the shrines in Iraq.