In May, according to Agence France-Presse, Saudi Arabia released Bakr bin Laden—now in his seventies, who has been the patriarch of the bin Laden family since the late nineteen-eighties—after almost four years of detention. He had been confined along with other out-of-favor royals and wealthy Saudi businessmen accused of corruption—without public charges or trials—by Mohammed bin Salman, or M.B.S., the ambitious and authoritarian crown prince of Saudi Arabia, who is trying to remake the kingdom’s political economy. Although bin Laden reportedly may now receive visitors, “he was told to stay home,” a source told the A.F.P.

Bin Laden has roots in Jeddah, the Red Sea port city where, in 1931, his father, Mohammed bin Laden, a poor migrant from Yemen, founded and built a construction company that grew eventually into the largest in the kingdom, as part of the family’s flagship conglomerate, the Saudi Binladin Group. It built palaces, renovated mosques in the holy cities of Mecca and Medina, and expanded across the Arab world. And, of course, it was part of the upbringing of Osama bin Laden, another of Mohammed’s sons, who studied business administration and apprenticed at the family firm before taking up jihad full time.

Bakr bin Laden’s recent travails offer a coda to the story of 9/11’s aftermath inside Saudi Arabia. The recent fall—or at least the economic punishment—of the bin Laden family has coincided with the rise to power of M.B.S., but it also reflects the twilight of the sprawling generation to which Osama belonged. It is a story of privilege, succession, and wildly diverse outlooks within a family whose name is an indelible part of American history.

Mohammed bin Laden died in a private-plane crash, in Saudi Arabia’s southern desert, in 1967, at the age of about sixty. He left behind fifty-four children, whom he had fathered by more than twenty wives. At the time of Mohammed’s death, his eldest son, Salem, was twenty-one and living in London, where he wore jeans and played rock-and-roll guitar and harmonica. Although hardly prepared for his new responsibilities, Salem took charge of the family and its businesses in the manner of a sheikh, and ran it as his fiefdom. He proved to be a charismatic globe-hopper who piloted Learjets, flew hot-air balloons and ultralights, and sang corny tunes (“On Top of Old Smokey” was a favorite) on just about any stage that he could find. Salem bought property in England and in the United States, including a home near Disney World, west of Orlando. In Saudi Arabia, he charmed the family firm’s most important patron, King Fahd, who reigned from 1982 until he suffered a debilitating stroke, in 1995. Fahd effectively controlled contracts that were important to the Saudi Binladin Group, and Salem became part of his court.

In the nineteen-eighties, Salem visited Osama, his younger half brother, in Pakistan, where he had joined the mujahideen fighting against the Soviet occupation of Afghanistan. At the time, Osama’s participation in that war, which had the backing of both King Fahd and Ronald Reagan’s C.I.A., was an uncontroversial matter. But, in 1988, Salem died in a freak ultralight accident outside San Antonio. He was forty-two. His death unmoored the bin Ladens, and, in the aftermath, Osama became increasingly radical and defiant of the Al Saud royal family, on the ground that it wasn’t Islamic enough and was too close to the United States.

During the several years that I spent researching a book about the bin Ladens, many family members and friends told me that Salem had had a way of keeping Osama in line, and that after his death Osama’s ego and sense of entitlement to leadership swelled. He seemed to believe that he was qualified to run the family after Salem. But he was not from the inner circle of Mohammed’s children. He was the only child of a teen-age girl whom his father had married and divorced hastily in the late nineteen-fifties. Osama was by no means the only child of Mohammed’s in this position, as his father married and divorced many women. Mohammed did fully enfranchise all his children as his heirs, and made them eligible for what was, during the nineteen-seventies, a tax-free allowance of several hundred thousand dollars a year. But Osama was not among the oldest or the best-connected of his father’s sons. In the end, Bakr, one of Salem’s full brothers, took charge of the family.

Bakr had lived in the United States for several years, where he obtained a degree in civil engineering from the University of Miami. Soon after he took over the family and the company, the Saudi government moved to expel Osama and strip him of citizenship, because of his unrelenting criticism of the royal family. Bakr correspondingly removed him as a shareholder in the family firms. In 1991, Osama went into exile, settling in Sudan and, later, in Taliban-ruled Afghanistan, from where he plotted 9/11.

Bakr’s greatest achievement as the family patriarch was to preserve access to lucrative royal contracts after King Fahd’s stroke. The new de-facto ruler was Fahd’s half brother Abdullah bin Abdulaziz, the crown prince. After 9/11, Abdullah protected the bin Ladens, refusing to punish them for Osama’s terrorism or to blame them for the ignominy that Saudi Arabia suffered, particularly in the United States. The contracts kept coming. Bakr pulled this feat off “thanks in part to a keen understanding of what the Al Saud wanted,” just as his father and Salem had done, the Wall Street Journal reporters Bradley Hope and Justin Scheck write in their book, “Blood and Oil.” “If that meant building a palace for a new wife in a matter of months, they’d get the job done. Payment could come much later or never at all; the Bin Ladens wouldn’t make a peep.”

Osama certainly had a few sympathizers among his many brothers and sisters, but the majority of them abhorred his violence and resented the damage he caused them. His killing, in Pakistan, by U.S. Navy SEALs, in May, 2011, relieved the family of any further association with his millenarian terrorism. The bin Ladens might have thrived indefinitely after Osama’s death but for the ambitions of M.B.S., who sought to marginalize rival factions in the Saudi élite while simultaneously authoring economic and social reforms, establishing himself as the most visible and powerful leader in the kingdom. Early in his rise, in 2015, according to a Reuters investigation, the crown prince met with Bakr and asked to become “a partner” in the Saudi Binladin Group, and suggested that Bakr take the company public by listing shares on the Saudi stock exchange. On September 11th of that year, one of the firm’s cranes fell in Mecca, killing more than a hundred people and injuring some four hundred. The Saudi government temporarily suspended contract awards to the bin Ladens. (The eerie coincidence of the date of the accident is one of a number of odd resonances in the bin Laden family history; another is the recurrence of traumatic plane crashes.)

In 2017, M.B.S. staged a broad crackdown on businessmen, in the name of fighting corruption. Bakr and two of his brothers, Saad and Saleh, were among the hundreds of wealthy Saudis detained, many of them at the Ritz-Carlton in Riyadh, where they had to answer allegations of financial crimes. According to the Reuters investigation, the authorities ultimately seized deeds to bin Laden family homes, private jets, luxury cars, cash, and jewelry.