<Li> From the mid-20th century the discovery of vast oil deposits propelled it into a key economic and geo - political role . </Li> <P> At other times, the region existed in relative obscurity and isolation, although from the 7th century the cities of Mecca and Medina had the highest spiritual significance for the Muslim world, with Mecca becoming the destination for the Hajj pilgrimage, an obligation, at least once in a believer's lifetime, if at all possible . </P> <P> For much of the region's history a patchwork of tribal rulers controlled most of the area . The Al Saud (the Saudi royal family) emerged as minor tribal rulers in Najd in central Arabia . From the mid-18th century, imbued with the religious zeal of the Wahhabi Islamic movement, they became aggressively expansionist . Over the following 150 years, the extent of the Al Saud territory fluctuated . However, between 1902 and 1927, the Al Saud leader, Abdulaziz, carried out a series of wars of conquest which resulted in his establishing the Kingdom of Saudi Arabia in 1930 . </P> <P> From 1930 until his death in 1953, Abdulaziz ruled Saudi Arabia as an absolute monarchy . Thereafter six of his sons in succession have reigned over the kingdom: </P>

When was the kingdom of saudi arabia created