The founder of the modern kingdom of Saudi Arabia and its first king. The al-Saud family brought about the remarkable transformation since Saudi Arabia's birth in 1932. Named after an 18th-century ancestor, Saudi royal family has crafted an absolute monarchy ruled by consensus within the family and by its alliance with the clerics. From the mid-18th century until defeated by rivals in the 1890s, Abdul Aziz's Saudi clan held Nejd in central Arabia, in alliance with the puritan, conservative Islamic Wahabi movement. In 1901 the young Abdul Aziz moved to capture the Saudi capital Riyadh, taking eastern Arabia from the Turks and establishing himself as Sultan of Nejd and its dependencies. Although benevolent towards the Allies in the First World War, he had to accept their sponsorship of the Hashemite rulers of the Hejaz for leadership of the Arab revolt against the Turks. After the Turkish collapse in 1918 he negotiated his borders with Iraq, Transjordan and Kuwait, and in 1924 drove out the Hashemite and occupied the Islamic holy places in 1925. He consolidated his rule throughout the Arabian Peninsula except for independent Yemen and the coastal regions under British protection. King Abdul-Aziz's many - politically astute - marriages helped shape and control his vast kingdom, exploiting tribal loyalties that persist to this day. King Abdul-Aziz is thought to have had roughly 70 children. They and their offspring form a core of about 200 princes who wield most of the power. But estimates of the total number of princes range anywhere from 7000 upwards, with most receiving stipends from Saudi oil revenues. Their unchallenged power and lavish lifestyle have stoked criticism outside and inside the kingdom. It was King Abdul-Aziz's close alliance with the US that helped him ward off threats towards the nascent state. He signed a concession agreement with Standard Oil of California (now Chevron) in 1935. The Company later established a subsidiary in Saudi Arabia called the Arabian American Oil Company (Aramco), now fully owned by the Saudi government. Saudi Arabia holds 20 per cent of the world's proven oil reserves, and its oil exports, the world's largest, prop up its $4000bn economy.