The political focus of the Muslim world then shifted to the newly conquered territories. Nevertheless, Mecca and Medina remained the spiritually most important places in the Muslim world. The Qur'an requires every able-bodied Muslim who can afford it, as one of the five pillars of Islam, to make a pilgrimage, or Hajj, to Mecca during the Islamic month of Dhu al-Hijjah at least once in his or her lifetime. The Masjid al-Haram (the Grand Mosque) in Mecca is the location of the Kaaba, Islam's holiest site, and the Masjid al-Nabawi (the Prophet's Mosque) in Medina is the location of Muhammad’s grave; as a result, from the 7th century, Mecca and Medina became the pilgrimage destinations for large numbers of Muslims from across the Islamic world. Middle Ages Despite its spiritual importance, in political terms Arabia soon became a peripheral region of the Islamic world, in which the most important medieval Islamic states were based at various times in such far away cities as Damascus, Baghdad, and Cairo. However, from the 10th century (and, in fact, until the 20th century) the Hashemite Sharifs of Mecca maintained a state in the most developed part of the region, the Hejaz. Their domain originally comprised only the holy cities of Mecca and Medina but in the 13th century it was extended to include the rest of the Hejaz. Although, the Sharifs exercised at most times independent authority in the Hejaz, they were usually subject to the suzerainty of one of the major Islamic empires of the time. In the Middle Ages, these included the Abbasids of Baghdad, and the Fatimids, Ayyubids, and Mamluks of Egypt. Modern history The provincial Ottoman Army for Arabia (Arabistan Ordusu) was headquartered in Syria, which included Palestine, the Transjordan region in addition to Lebanon (Mount Lebanon was, however, a semi-autonomous mutasarrifate). It was put in charge of Syria, Cilicia, Iraq, and the remainder of the Arabian Peninsula. The Ottomans never had any control over central Arabia, also known as the Najd region. The emergence of what was to become the Saudi royal family, known as the Al Saud, began in Najd in central Arabia in 1744, when Muhammad bin Saud, founder of the dynasty, joined forces with the religious leader Muhammad ibn Abd al-Wahhab, founder of the Wahhabi movement, a strict puritanical form of Sunni Islam. The Emirate of Diriyah established in the area around Riyadh rapidly expanded and