The concept of "Rightly Guided Caliphs" originated with the later Abbasid Caliphate based in Baghdad. The Rashidun caliphate expanded very quickly under Muhammad and the first three caliphs. Several caliphs and emirs owned vineyards and drank wine. The Sunnis recognize the first four caliphs as Muhammad's rightful successors. The first mamluks served the Abbasid caliphs in 9th-century Baghdad. The first two Caliphs, Abu Bakr and Umar are buried next to Muhammad. Tughril Beg saw himself as the protector of the Abbasid Caliphs. The Abbasid Caliphs in Baghdad, such as Al-Mu'tadid, were often cruel in their punishments. Historical accounts differs on what happened to Fadak under the early Abbasid caliphs. Iltumish however denied this to him in deference to the relationship with the Abbasid caliphs. Al-Wathiq is one of the more obscure Abbasid caliphs. Under the first four Caliphs, Persia remained predominantly Zoroastrian. Additions and renovations were carried during the reign of the remaining Fatimid caliphs. The first four caliphs, and the Ummayads caliphs and provincial governors all delivered sermons. Thereafter, hereditary succession became the standard practice of the Umayyad caliphs.