The Ottoman Caliphate, under the Ottoman dynasty of the Ottoman Empire, was the last Sunni Islamic caliphate of the late medieval and the early modern era. During the period of Ottoman growth, Ottoman rulers claimed caliphal authority since Murad I's conquest of Edirne in 1362. Later Selim I, through conquering and unification of Muslim lands, became the defender of the Holy Cities of Mecca and Medina which further strengthened the Ottoman claim to caliphate in the Muslim world.