The Saud family saw its fortunes rise and fall over the next 150 years as heads of the tribe clashed with Egypt, the Ottoman Empire, and other Arabian clans.
The family was even expelled at the end of the nineteenth century and exiled briefly in Kuwait.
Production grew steadily in the decades after the second world war. But the kingdom only began to enjoy major oil wealth after it and other Arab oil-producers started raising prices in the early 1970s and Saudi Arabia found new, vast petroleum reserves.
After the 1973 Arab-Israeli war and the Arab oil boycott of the US and the Netherlands over their support of Israel, soaring petrol prices sent oil revenues rocketing.
Large numbers of immigrants came to support the flourishing economy while native Saudis led heavily-subsidised lives, enjoying free healthcare, free education and no taxes.
The kingdom has failed to diversify
its oil-based economy
But Saudi Arabia suffered sharp drops in its oil revenues as prices fluctuated and declined in the 1980s and 1990s.
Attempts to diversify the oil-reliant economy largely failed: The petroleum sector still accounts for about 75% of budget revenues and 90% of export earnings.
The slowing economy, together with high birth rates in recent decades and continuing dependence on foreign labour have resulted in rising unemployment among young Saudis in particular.
Up to 20% of Saudis - some dissidents say more - are jobless.
Government and politics
The constitution is framed according to sharia or Islamic law. A Basic Law that details the government's rights and responsibilities was introduced in 1993.
The legal system is similarly based on Islamic law, although several secular codes have also been introduced. Commercial disputes are handled by special committees.
The large Saudi royal family has kept a tight rein on the administration.
1932 Abd al-Aziz declares himself king
1938 Oil discovered in kingdom
1953 Abdul Aziz dies, succeeded by son Saud
1964 King Saud abdicates in favour of half-brother Faisal, who stresses economic development
1975 King Faisal killed by nephew, succeeded by half-brother Khalid.
1982 Khalid dies; brother Fahd becomes king
1990-91 King Fahd joins US-led coalition and urges Arabs to help expel Iraq from Kuwait
1995 Fahd suffers a stroke. By late 1997, Crown Prince Abd Allah is running the government
2003 Amid increasing crackdown on armed dissidents, Riyadh bombings kill 35 in May
2004 Attacks targeting foreign workers in oil-related industries leave 27 dead in May
Virtually all key posts are occupied by one of the hundreds of Saudi princes. Other senior officials are appointed.
There is no elected legislative assembly. Instead, the king is advised by a consultative council or shura of 90 members and a chairman appointed by the monarch to serve for four years at a time.
There are no permitted political parties or official opposition, but the struggling economy has fuelled popular dissatisfaction with the US-backed regime and fed demands for political reform and greater democracy, mainly from political dissidents, often based abroad.
The 2001 attacks on the US and the 2003 US-led invasion of Iraq have placed fresh pressures on the kingdom.
Many in the US have increasingly criticised its ally's relationship with certain Middle Eastern armed organisations.
Conversely, many religious Saudis feel the regime has betrayed its Islamic roots by allying with a country that supports Israel and attacks or helps suppress Muslim societies.