Almost the entire Middle East and North Africa came under Ottoman rule during the first half of the sixteenth century. Selim I’s forces took over the heartland of the Arabic-speaking world, mainly Syria and Egypt, in a major campaign during  and  against the ailing Mamluk sultanate. Iraq (and parts of Iran) fell to the Ottomans under Süleyman in . North Africa, excluding Morocco, was taken in the mid-to late s, and finally Yemen in . Thereafter, the Ottoman sovereigns reigned over a Muslim-majority empire, the largest Islamic state of the early modern and modern eras and the undisputed leader of Sunni Islam. They boasted sovereignty over Mecca and Medina in the Hijaz, where the holiest shrines of Islam rested, and consequently became protectors of the pilgrimage routes to Arabia. The conquest of Iraq also meant that, for centuries to come, the Ottomans faced a formidable rival on their eastern frontiers, the Shi’ite dynasties of Iran.