When Salman bin Abdulaziz al-Saud was born in 1935, the country he would one day rule was only three years old. The Saudi Arabia of Salman's birth had not yet discovered oil. The vast majority of its citizens were poor, nomadic or semi-nomadic Bedouin, and would remain that way for decades. Merely crossing the vast, harsh country was considered unsafe or simply impossible. Most earned their living from animal husbandry up through the 1960s. The nation did not end slavery until 1962, when Salman was 27 years old. This week, at age 80, Salman's older brother, King Abdullah, has died, and Salman became king.

During Salman's lifetime, Saudi Arabia has transformed and it hasn't. It is still in many ways defined by the ultra-conservative Islam, and by the monarchy's tangled relationship to fundamentalism, which famously includes, for example, treating women as the cattle-like property of men and conducting public beheadings. As the world's second largest producer of crude, it is also defined by its oil, which has brought fantastic wealth and power to what had been one of the world's poorest countries. And it is defined by its quietly world-changing foreign policy, which paradoxically supports both the United States and anti-Western jihadists.

The country is as complex as it is little-understood among Americans; here, then, is an attempt to answer some of your most basic questions about Saudi Arabia.

1) What is Saudi Arabia?

Saudi Arabia is a fundamentalist Islamist dictatorship, an ultra-wealthy oil economy, and perhaps the most powerful country in the Middle East. It is a very young country in a very old part of the world. It formed in 1932, when a tribal leader named Abdulaziz al-Saud conquered an area three times the size of Texas and then named it after himself. He and his first generation of sons have ruled Saudi Arabia ever since.

The way that Abdulaziz al-Saud came to conquer and unify this country is crucial for understanding it: by allying with a fiercely conservative group of Islamist fundamentalists known as the Wahhabis. Saudi Arabia became "the only modern nation-state created by jihad," as the journalist Steve Coll once put it.

The Saudi royal family and the cult-like Wahhabis have needed one another ever since — but they have also regularly been in conflict, often violently. This struggle, which became even more intense with the arrival of vast oil wealth, has in many ways defined the nation ever since. And it has defined Saudi Arabia's foreign policy, which helped shape not just the modern Middle East but in some ways the world.

There's another way to look at Saudi Arabia that helps explain the internal struggles that have so defined it: as three distinct societies forced together by al-Saud's conquests just 80 years ago. "Think of central Arabia as being in three parts — the oil fields in the east, the holy cities of Mecca and Medina in the west, and the largely barren desert in the middle," Robert Lacey wrote in his 2010 history of Saudi Arabia:

At the beginning of the 20th century, and for most for most of the previous centuries of Arabian history, those three geographical units were separate countries and, to some degree, cultures. It was the modern achievement of the House of Saud, through skilled and ruthless warfare, a highly refined gift for conciliation, and, most particularly, the potent glue of their Wahhabi mission, to pull those three areas togethers so that, by the end of the 20th century, the world's largest oil reserves were joined, sea to sea, to the largest center of annual religious pilgrimage in the world — and to their capital in the Wahhabi heartland of Riyadh.

2) Where does Saudi Arabia's ultra-conservative version of Islam, Wahhabism, come from?

This story goes all the way back to 1744, when the ambitious but unremarkable clan of al-Saud, one of many clans that divided up the vast Arabian desert, allied with a puritanical fundamentalist named Muhammed ibn al-Wahhab.

Mecca and Medina, on the Arabian peninsula's western coast, are the holiest cities in Islam, the places of the religion's 7th-century birth, and Muslims are theologically required to make a pilgrimage there at least once in their lives. In the 1700s, many of those pilgrims came from Egypt and Ottoman Turkey, at the time wealthy and cosmopolitan places. Meanwhile, Islam on the impoverished and uneducated Arabian peninsula had become tinged with superstition and idolatry. All of this infuriated Wahhab and his followers, who wanted to cleanse Islam and revive what they saw as the faith's true roots — which, in their not-always-accurate interpretation, meant an austere, ultra-conservative, and stern Islam.

The al-Saud clan allied with Wahhab and his followers, known as Wahhabis, who in their fervor could fight as well as preach. The deal was simple: the Wahhabis would help the al-Sauds expand through conquest from a tiny sliver in the Arabian peninsula's central desert to a vast empire, and in return the al-Sauds would adopt Wahhabism as official policy. It worked: by the early 1800s the al-Sauds had come to control virtually all of what we today consider Saudi Arabia, and Wahhabist clerics had become immensely powerful, their fundamentalist movement now in charge of Islam's holiest sites.

This empire — officially called the Emirate of Diriyah for the al-Saud's home city, but sometimes known as the "first Saudi state" — collapsed in 1818, defeated by the much stronger Ottoman Empire, which seized much of the Arabian peninsula for itself. But Wahhabist Islam had taken root, and the Wahhabis and the al-Sauds maintained their strategic alliance from 1744 through today.

3) Why is fundamentalist extremism the official policy of Saudi Arabia?

Because Saudi rulers need the Wahhabis' support to stay in power. They need their loyalty, they need the civil society that the Wahhabi clerical establishment creates, and they also need the ideological justification for the vast, young, and in many ways artificial Saudi empire. But the Saudis also know they need to be a part of the modern world, which the Wahhabis hate. That tension has in many ways defined Saudi Arabia from the start, and it has often come to bloodshed.

When Abdulaziz al-Saud was born, in 1876, the area we today know as Saudi Arabia was a patchwork of tribal leaders, many of them loyal to the Ottoman Empire or, later, the British Empire. Abdulaziz wanted to restore his family's former empire. He knew that, like his forefathers, he would need the help of the Wahhabis and the zeal they brought to the battlefield. So he formed a band of quasi-renegade fundamentalist militias known as the Ikhwan, or brothers. As before, the deal was simple: the Ikhwan would fight on behalf of al-Saud, and in exchange could impose their ultra-conservative Islam on whomever they conquered.

But the world had changed since the late 1700s, and by the early 1900s so had Wahhabism. It was no longer just about opposing liberal Islam or superstition, but about opposing modernity itself, which had crept onto the Arabian peninsula. Technology, alcohol, automobiles, the slightest hint of gender equality, the presence of non-Muslims, even embroidery were cause for severe punishment.

Then something happened that is crucial for understanding Saudi Arabia and its relationship to fundamentalism. By the late 1920s, al-Saud and the Ikhwan had conquered most of today's Saudi Arabia. Al-Saud, a pious Muslim but also a forward-thinking pragmatist, began to modernize his new empire. This infuriated the Ikhwan, who saw it as a betrayal. Then the Ikhwan began to attack neighboring British-held territory, which they hoped to "liberate." Al-Saud had forbidden this, wishing to remain friendly with the powerful British Empire. The al-Saud clan and Ikhwan fell into open warfare, which ended when al-Saud used modern machine guns to defeat the camel-riding Ikhwan at the 1929 Battle of Sabilla.

After the battle, al-Saud tried to head off future uprisings, but retain the loyalty of the Wahhabis whose support he needed in order to ideologically justify his new nation, by cynically co-opting their fundamentalism as his own. He created the Ministry for the Propagation of Virtue and the Prevention of Vice, better known as the religious police, a fanatical and semi-autonomous band of ideological enforcers who are still an official body of the Saudi state today.

4) But that was so long ago. Why is modern Saudi Arabia still so fundamentalist? Why does it stick to such backwards ideas?

The pattern of the 1920s, in which the Saudi rulers need Wahhabi fundamentalists, then come into conflict with them over modernization, and ultimately co-opt that fundamentalism in order to neutralize it, has repeated throughout Saudi history. That pattern has shaped Saudi Arabia's severely oppressive rule at home and its support of jihadism abroad.

In the 1960s and especially 1970s, an explosion of oil wealth began to transform Saudi Arabia, by bringing in the modernizing force of outside investment, by allowing Saudis to afford more modern goods and lifestyles, and by Westernizing the governing elite with British and American educations. The Wahhabis, alarmed, launched a still-ongoing culture war that has at times targeted the monarchy and has included real casualties.

In 1965, a Wahhabist group in the holy city of Medina launched a campaign called "the destruction of the pictures" to destroy any "idolatrous" and thus heretical photos in public places — including official portraits of the king. That same year, when the country first received television, Wahhabi protesters violently stormed a TV studio; one of the protesters was killed by police. A decade later, his brother assassinated the Saudi ruler, King Faisal, in retaliation.

But the most violent clash between the Saudi government and the Wahhabis came in 1979, with the traumatic Siege of Mecca, perhaps the most significant event in modern Saudi history. An armed band of apocalyptic Islamist cultists seized the Grand Mosque in Mecca, Islam's holiest site, from which they denounced the Saudi royal family as hypocritical "drunkards" who had betrayed Islam, which they intended to purify. By the time French commandos ended the siege, hundreds of the cultists' hostages had been killed.

The Saudis saw the siege as part of a dangerous wave of anti-government extremism — Islamists were also in the process of toppling the monarchy in nearby Iran — and responded by cracking down on dissent of all kind, as well as by aggressively co-opting ultra-conservative Islamism, forcing new restrictions, especially on women, to appease the Wahhabis.

Those practices remain today, born out of fear of another violent uprising. The country's vast, paranoid security services target Islamists and liberals alike, most recently sentencing a young blogger to 1,000 public lashes for writing about atheism. And its religious police enforce medieval social mores, such as the status of women as the powerless property of men.

5) Can we take a music break?

Yes, even if only to challenge the widespread Western misconception of Saudi Arabia as a joyless, humorless place where things like music and humor are forbidden or despised. There is an officially-enforced degree of truth to that perception (most public music was banned after the 1979 siege of Mecca, to appease Islamists), but it's far from the whole truth; plenty of Saudis love music. Contemporary musicians include, for example, beloved pop singer Mohammed Abdu (so catchy!) and Saudi-Iranian YouTube star Alaa Wardi, who later formed the great rock band Hayajan. Here's my favorite song off their first album:

Wardi is a member of Saudi Arabia's young, liberal, cosmopolitan generation. The country's official ultra-conservatism does not exactly make for great live music or comedy club scenes, but the internet has changed that, opening up a freer and more easily interconnected world of creative expression and consumption.

The most famous may be Fahad Albutairi, a young comedian whose ultra-popular YouTube show La Yekhtar ("Zip It") is a sort of online-only variety show, featuring monologues and skits that are funny, polished, and often comment quite freely on social and political issues. Here's one of my favorite episodes (be sure to turn on the English captions); the first four minutes are a comment on corruption that will be inaccessible to most outsiders, but the rest is a satire on Saudi and Western cultural interactions, first on MIA's 2013 music video showing drag racing in a Saudi desert, then on Saudi exchange students who go to live in the US. It's really funny:

In 2013, as Saudi Arabia's law forbidding women from driving cars again entered the news (a number of Saudi women had protested the ban by posting videos of themselves driving on YouTube), Albutairi, along with Wardi and a Saudi comedian named Hisham Fageeh recorded a viral music video satirizing the law, "No Woman, No Drive," based on the Bob Marley song. The song subtly but harshly criticized the law; like the women who had driven in protest (often with the support of male family members), it was a reminder that the ultra-conservative Wahhabists may be a powerful force in Saudi Arabia, but they do not represent everybody.

6) Why does Saudi Arabia support jihadists?

This also goes back to the 1979 Siege of Mecca. Since then, the Saudis have attempted to reduce the threat of Islamist extremism at home by redirecting it abroad, turning jihad into a sort of quasi-official foreign policy.

That same year, the Soviet Union invaded Afghanistan. The Saudi government, which hated the Soviets and saw them as a threat, sought to support Afghan rebels. Here was an opportunity: the Muslim world was outraged by the Soviet invasion. The Saudi government implicitly encouraged their country's Wahhabi clerical establishment, recently rich with oil money and dangerously idle, to fund extremist Afghan rebels, and rebel-training extremist madrassas in neighboring Pakistan. Many young Saudi Wahhabis went off themselves to fight, usually quite poorly.

For the Saudi rulers, this foreign policy of jihad was at first a great success. It strengthened Saudi Arabia's effort to fund Afghan rebels, it positioned the often-lecherous Saudi monarchs as leaders of the Muslim world against the Soviet atheists, and, crucially, it distracted the Wahhabis from causing trouble at home.

But this strategy was destined to backfire, and disastrously. Those jihadists would inevitably turn their guns on the very Saudi government that had enabled their creation, just as the Ikhwan of the 1920s and the cultists of the 1970s had done. The most famous of those was Osama bin Laden.

In 1991, Saudi Arabia again faced much the same problem it had in 1979. Iraqi leader Saddam Hussein invaded Kuwait; the Saudis, fearing they could be next, invited the US military to station thousands of troops in the Kingdom. The Wahhabis were outraged, seeing this as a humiliation and a desecration of Muslim holy land, and openly hinted they might support a coup or violent uprising. Meanwhile, many Saudi jihadists had returned home from Afghanistan, giving the threats real teeth.

Fearing another 1979-style terror attack of worse, the Saudis once again co-opted and appeased the Wahhabis. They did this in part by shutting down some nascent reforms — some women had begun to drive in defiance of the female driving ban; initially tolerated, they were shut down. They also established the Ministry of Islamic Affairs, which ostensibly supported Islamic charities but also funded Wahhabi extremism and jihadism throughout the Muslim world. It worked; the Wahhabi establishment directed their energies toward causing trouble abroad, which the Saudis tolerated. At the same time, the Saudis also cracked down on Wahhabists who would not get in line, including by deporting a well-known veteran of the Afghan jihad named Osama bin Laden.

7) Did Saudi Arabia support Osama bin Laden and/or the 9/11 attacks?

At first, yes. Famously, bin Laden's father grew up poor and uneducated, but through hard work and careful connections turned his small construction business into the unofficial contractors of the Saudi royal family, and became a billionaire. Osama, who like many Saudis of his generation grew up disillusioned and confused by the collision of old and new in the kingdom, used his slice of the family fortune in the 1980s to go fight the Soviets in Afghanistan. There, he met other Arab jihadists, with whom he formed al-Qaeda in 1988. The Saudi government, which along with the US backed the Afghan jihad as official policy, supported bin Laden. He came home in 1990 a national hero.

Saudi Arabia began its break-up with the jihadists, including bin Laden, that same year. Bin Laden personally met with Prince Sultan, the national defense minister, to ask permission to lead his jihadist fighters against Saddam's armies in neighboring Kuwait. When Sultan refused, bin Laden turned against the monarchy, publicly condemning it and questioning its legitimacy. In 1992, Saudi Arabia revoked his citizenship and expelled him to Sudan. In 1996, under US pressure, Sudan expelled him to Afghanistan.

By 1996, bin Laden had come to blame his problems, and the problems of the Muslim world, on the United States, which he saw as a heretical imperial power little different from the Soviet Union. He had also maintained his ties to fellow Arab veterans of the Afghan jihad, including an Egyptian named Ayman al-Zawahiri. His particularly Egyptian brand of extremism was distinct from bin Laden's Wahhabism — Zawahiri's rage focused on the dictatorships of the Arab Middle East — but they agreed that salvation could only come through defeat of non-believers, which to them included the Saudi royals, and the establishment of a vast pan-Islamic empire.

Saudi Arabia was well aware of the threat posed by bin Laden and the movement he represented. As always, though, the Saudis played a double-game: they disavowed bin Laden but were one of only three countries, along with Pakistan and the United Arab Emirates, to officially recognize the Taliban, an extremist group that had seized Afghanistan by force and officially sheltered bin Laden and al-Qaeda.

This double-game is part of why so many Americans still wonder if Saudi Arabia could have played some role in the September 11 attacks, though it would have nothing to gain and everything to lose by sponsoring such an attack on its most important ally. Another reason is that the Bush administration, which has longstanding ties to the Saudi royal family, ordered that the Joint Congressional Inquiry into the attacks permanently seal 28 pages in its report that investigated possible Saudi links to the attack.

Some members of Congress who have read the report describe it as damning. An unnamed member of Congress told the New Yorker, "The real question is whether it was sanctioned at the royal-family level or beneath that, and whether these leads were followed through." Other officials, though, say the findings are speculative and inconclusive, and that their release would cause unwarranted damage to the fragile US-Saudi alliance.

The most common theory, hinted at by evidence and testimony described by the New Yorker and other reputable journalists, points to rogue officials within the Saudi government's Ministry of Islamic Affairs, or people supported by those officials, as having provided crucial support to the 9/11 hijackers during their stay in the United States. For example, a Saudi living in the US who had ties to the Islamic Affairs Ministry, and who was salaried by a Saudi aviation company for whom he never actually did any work, facilitated and paid for an apartment for two of the hijackers. His US-based contact in Islamic Affairs, Fahad al-Thumairy, was expelled in 2002 over suspected ties to terrorists.

If the 9/11 attackers were somehow facilitated or funded by Saudis within or connected to Saudi Ministry of Islamic Affairs, this would be nowhere near the same thing as official Saudi policy. Simple logic makes clear the Saudis would never support an attack on their ally and patron, and conspiracy theories to the contrary make as much sense as accusing Israel or George W. Bush of responsibility. At the same time, it would be within the realm of possibility — and, indeed, would be consistent with the history of self-defeating Saudi policies — if Saudi Arabia's short-sighted support for jihadism had unintentionally allowed extremists within Islamic Affairs to divert funds to the hijackers. Saudi Arabia's support for extremism has been blowing up in its face since the 1920s; it was perhaps only a matter of time until it blew up in our face as well.

8) Why is America so close with this ultra-conservative, jihadist-supporting country?

The foundation of the US-Saudi alliance is not, despite widespread assumption to the contrary, primarily about oil. It's true that FDR began building close ties with Saudi Arabia during World War II out of strategic interest in maintaining ready access to oil, and it's true that official US policy since President Carter has been to maintain the free flow of oil out of the Middle East.

But there are two misconceptions here. First of all, the US actually buys a relatively small percentage of its oil directly from Saudi Arabia (although it does care about maintaing Saudi exports, which are important to the global economy more broadly); the US imports almost as much oil from Venezuela, which is more enemy than ally. In any case, Saudi Arabia's protectionist and heavily nationalized oil industry hasn't been very open to Western oil companies for years. Second of all, the US-Saudi alliance has always been built much more on shared foreign policy and security interests than on oil.

The alliance goes back to the Cold War, when Saudi Arabia worked closely with the US against the Soviet Union, which it saw as an ideological and physical threat. "The Saudi royals, so hostile to Marxist atheism that they did not even maintain diplomatic relations with the Soviets, has quietly collaborated with the CIA against Moscow for decades," Steve Coll writes in his Pulitzer-winning history, Ghost Wars. In this 1970s, before even President Carter made it official US policy to protect Middle Eastern oil exports, this included facilitating contacts between the CIA and religious pilgrims visiting Mecca from heavily Muslim Soviet Central Asia. It also included sending Saudi Arabia's formidable intelligence service to work alongside US, British, and French agents in Muslim parts of Africa to undermine Soviet influence there.

The US-Saudi alliance really blossomed, though, in 1979 with the Soviet invasion of Afghanistan. The Saudis believed this was a first step toward exerting Soviet control over, and spreading leftist atheist influence within, the oil-producing states of the Middle East. That they were wrong didn't matter; Saudi Arabia and the US began collaborating closely on turning Afghanistan into the Soviet Union's Vietnam, a project that took a decade of work and built the close intelligence ties that remain to this day.

Prince Turki al-Faisal, the Saudi intelligence chief from 1977 to 2001, was heavily Americanized by his New Jersey boarding school and Georgetown education and used the Afghan conflict to build close relations with the CIA, State Department, and White House. He saw this as crucial for his country's strategic goals of exerting influence first against the Soviets and later against revolutionary Iran, which as a Shia theocracy was a natural enemy of Sunni Saudi Arabia. Prince Turki, in many ways the architect of the modern US-Saudi alliance, remains influential in both countries today.

The Afghan jihad also brought out the belief in both the Saudi and US governments that their countries shared common cultural values, as improbable as that might sound. Under the Reagan-era rise of a politically powerful Christian right, American evangelicals embraced the CIA- and Saudi-backed Afghan rebels as religious freedom fighters opposed to Soviet atheism. Some mujahideen were brought on tours of American evangelical churches to solicit donations. The Reagan White House particularly cultivated a sense among the Saudis that piety was a shared cultural value.

Even after the Soviets withdrew from Afghanistan in 1989, circumstance continued to bring the Saudis and Americans together against common enemies. First, both opposed Iran, and sought to weaken it during Iran's decade-long war with Saddam Hussein's Iraq. In 1990, Saddam invaded Kuwait — a tiny, oil rich kingdom between Iraq and Saudi Arabia — and Saudis feared they could be next. Some members of the royal family had even suggested previously to the CIA that Saddam be removed in a coup. This prompted another decade of intelligence and military cooperation, this time against Saddam.

With 2001, the US and Saudi Arabia began working together against a common enemy that the Saudis had already been fighting for years: violent Islamist extremists. Saudi intelligence services had agents throughout the Muslim world sniffing out jihadist threats to the Kingdom; the US was under-resourced in these countries and badly needed help, which the Saudis were happy to provide. The global war on terror, as George W. Bush termed it, in many ways repeated the grand US-Saudi strategic alliance against the Soviet Union.

At its most basic level, the US-Saudi alliance has been driven by a shared interest in maintaining the status quo in the Middle East. This status quo is some ways about oil, but in the conflict-riven Middle East, security and stability are much more important foundations for the status quo than is oil. This helps explain why Saudi Arabia has been so assertive about projecting its influence across the Middle East, and why it works so closely with the US in every major Middle Eastern issue from the standoff with Iran to Yemen's political crisis to Syria's civil war.

However, the Arab Spring uprising of 2011 brought a disagreement between the US and Saudi Arabia over the viability of that status quo, and thus a real fissure in the relationship. The US has intermittently supported democracy movements in the region, including those that have empowered populist Islamist movements such as the Egyptian Muslim Brotherhood. But the Saudis oppose both democracy movements and populist Islamist movements, both of which they fear could threaten their rule if they appeared in Saudi Arabia, and has worked to squash them throughout the region.

The question of whether the US and Saudi Arabia could be headed for a breakup, riven by irreconcilably different values, has hung over the relationship since its start. But as long as their are common enemies, and a common interest in the status quo, it is unlikely to change.

9) I skipped to the bottom. What does the future hold for Saudi Arabia?

The biggest concern among the Saudi royalty has always been, and will likely always be, stability. The Saudi state is so artificial that the royal family believes it can only hold power through continued dictatorship, propped up by the oil exports that allow it to fund lavish Saudi lifestyles.

There are four major threats to the Saudi system. The first is the risk of a political rift with, or even violent rebellion by, the powerful Wahhabi clerical establishment — a theme in Saudi history going back to its 1932 foundation. The second is the risk of an Arab Spring-style populist or liberal uprising, a danger that rises as more Saudis become interconnected by technology (Saudis have the highest Twitter usage per capita in the world) and as falling oil prices make it tougher for the monarchy to buy popular loyalty.

Third is the hazier risk of a succession crisis: the new crown prince is the last of founding king Abdulaziz's sons in line for the throne (those sons have ruled since Abdulaziz's 1953 death). Once the crown skips to the next generation, from Abdulaziz's sons to his grandsons, it becomes much less clear who is in line, and the risk of royal infighting or an internal fissure becomes much higher.

Fourth is the question of what happens once the oil runs out. Saudi Arabia's remaining reserves are a state secret. While it's unlikely that they'll be depleted tomorrow, they will likely be depleted, and no one is sure what happens to this country once its crude-based economy collapses.

In the meantime, Saudi Arabia will continue to pump oil, and that oil will continue to fuel the Saudi monarchy, the Wahhabi clerical establishment that has already spread Islamist extremism so far and wide, and the Saudi foreign policy makes it perhaps the most influential country in the Middle East.