In 622 c. E. the Prophet Muhammad began preaching the oneness of Allah. He migrated to Medina and founded the Islamic religion. He was able to add converts in Medina, so he returned to capture Mecca and designated Medina and Mecca as holy cities of his new religion. However, with the establishment of Umay-yad caliphate in Damascus in 661, the political center of Islam left the Arabian Peninsula, never to return.
Medieval Arabia was marked by continuing struggles of local and foreign rulers to gain control of the Arabian Peninsula. Most of these proclaimed obedience to the caliph but were essentially autonomous and independent. Modern Arabian history had its beginnings in the growing opposition to Ottoman rule, which began in the early sixteenth century, and the emergence of a reform religious movement in the early eighteenth century.
In 1745 Muhammad ibn 'Abd al-Wahhab began preaching the purification of Islam by excluding external and modern influences. He received the support of Muhammad ibn Saud of Dir'iyah, and the resulting Wahhabiyah movement spread across the Arabian Peninsula. Their successes were often stymied by Ottoman and Egyptian resistance, but fighting continued throughout the nineteenth century. The Saudi state was established in central Arabia in approximately 1750.
For the next 150 years, the Saudi rulers fought battles with Egypt, the Ottoman Turks, and other Arabians for control over the Arabian Peninsula. By 1904 Ibn Saud had recovered all of the original Saudi territory in Central Arabia (the Najd). Over the next twenty years he continued to fight for and annex land. In 1927 the British, who had held Saudi lands as a protectorate since 1915, acknowledged the independence and sovereignty of the kingdom of the Hejaz and Najd. In 1932 the modern Kingdom of Saudi Arabia was officially established from these land holdings.