King Abdul Aziz began conquering today's Saudi Arabia in 1902, by restoring his family as emirs of Riyadh. He then proceeded to conquer first the Nejd (1922) and then the Hejaz (1925). He progressed from Sultan of Nejd, to King of Hejaz and Nejd, and finally to King of Saudi Arabia (1932).
The other kings have all been sons of his, and Crown Prince Abdullah and his likely immediate successors are also sons of King Abdul Aziz "ibn Saud". Sons of Ibn Saud are considered to have primary claim on the Kingship of Saudi Arabia. It is intended that a family assembly choose heirs from their or the next generation at some time in the future, but the line of succession is never set beyond the appointed Crown Prince at any given time.
Since Crown Prince Abdullah is currently the de facto leader of the nation, it is assumed he will be the next king. After him, the most likely candidate to become king is his half-brother (and full-brother of Fahd) Crown Prince Sultan.
The King of Saudi Arabia is also considered the Head of the House of Saud.
It is interesting to note that although Saudi Arabia is ruled by Islamic law and purports to be an Islamic state, many Muslims see a monarchy as being against Islam. This attitude towards monarchy stems from Muhammad's own injunction against hereditary rule, and rather in favor of selecting rulers based on who is most qualified. However, it should also be noted that for most of Islamic history, the caliphate was a hereditary system.
SaudiArabia is the world’s largest exporter - sitting atop a quarter of the world’s known reserves - and the United States is the world’s largest energy consumer.
King Fahd, once a stickler who took a hand in the smallest details of government activities, stayed on the sidelines as the kingdom dealt with those crises.
Fahd, born in Riyadh in 1923, was proclaimed the fifth king of SaudiArabia on June 13, 1982.