The House of Al Saud traces its origins to the 18th century emir, Muhammad ibn Saud, whose family ruled large parts of the Arabian Peninsula for over three hundred years. The modern House of Saud was established in 1932, when Abd al-Aziz ibn Saud, a direct descendent of the 18th-century ruler, established the Kingdom of Saudi Arabia with himself as absolute monarch. Today, only his descendents are considered part of the "royal" family line and eligible to ascend the throne.

According to the Quran, a Muslim is permitted up to four wives at one time and is allowed to divorce and remarry numerous times. King Abd al-Aziz cemented alliances by marrying a daughter of every tribal chief in his realm, producing 45 legitimate sons and having at least 22 wives.

Every Saudi king since has been a son of Abd al- Aziz. The number of his daughters is not known - they were not counted - but are estimated to be more than 50. Though many of his contemporaries regarded his practice of polygamy as excessive, it was continued and surpassed by his son, King Saud, who had 53 sons and at least 54 daughters. The descendents of King Abd al-Aziz now number in the thousands, many of whom hold important government positions.

Before he died, King Abd al-Aziz established a line of succession: Future kings were to be chosen from among his own sons, beginning with the oldest surviving son, Saud, and followed by the second oldest, Faisal. To date, five sons have ruled: Saud (1953-1964), Faisal (1964-1975), Khalid (1975-1982), Fahd (1982-2005), and Abdullah (2005-present). Several of his other sons currently serve in the highest levels of government: Salman, Nayef and Sultan - three of the famous "Sudayri Seven," a close-knit group of seven sons born to a mother from the Sudayri tribe. But most of King Abd al-Aziz's sons are now in their eighties - King Abdullah is eighty-three - and the day will soon come when a Saudi king is chosen from the third generation of the Al Saud.