In the 17th century, Dutch settlers flocked to the southern half of what is now Manhattan to establish New Amsterdam, a fur-trading post that would welcome Lutherans and Catholics from Europe; Anglicans, Puritans, and Quakers from New England; and Sephardic Jews who were, at the time, discouraged from settling in America’s other nascent regions. Though its English conquerors would rename the city New York, the values of diversity and tolerance that the Dutch introduced would remain the region’s hallmarks for centuries to come.

In the modern-day Netherlands, however, the Dutch Republic’s founding pledge that “everyone shall remain free in religion” will soon collide with the ambitions of one of the country’s most popular politicians.

“Islam and freedom are not compatible,” claims Geert Wilders, the Party for Freedom (PVV) leader who campaigns on banning the Quran, closing Dutch mosques, and ending immigration from predominantly Muslim countries. “Stop Islam,” the phrase that sits atop Wilders’s Twitter page, aptly summarizes his party’s platform. In December, Dutch courts found Wilders guilty of carrying his rhetoric too far, convicting him of discriminatory speech for rallying supporters in an anti-Moroccan call-and-response. Nonetheless, Wilders is a leading contender to receive the plurality of votes in the country’s parliamentary elections on March 15.

The nation’s peculiar path from “live and let live” to “Make the Netherlands Ours Again” (as Wilders recently said) has as its guideposts a changing definition of tolerance, some instances of political opportunism—and a pair of grisly assassinations.

From the mix of faith groups that inhabited New Amsterdam to the peaceful coexistence of Protestants, Catholics, and socialists throughout the Netherlands in the 20th century, the Dutch brand of multiculturalism has often been more “salad bowl” than “melting pot.” Each sect of society had its own schools, media outlets, and social groups; tolerance was the act of respecting those boundaries.

“Historically, Dutch tolerance has been more of a pragmatic strategy,” said Jan Rath, a professor of urban sociology at the University of Amsterdam. “Tolerance has been a way to contain oppositions or complications.”

The same logic was initially applied to the wave of Turkish and Moroccan migrants who entered the Netherlands in the 1960s, when a substantial labor shortage prompted the Dutch government to welcome in many thousands of workers.

“They were supposed to have been temporary, to clean out oil tankers, work in steel factories, sweep the streets,” the academic Ian Buruma wrote in Murder in Amsterdam of the prevailing Dutch sentiments toward the Turkish and Moroccan workers at the time.

But when the jobs dried up after the 1973 oil crisis, the guest workers did not move back to their home countries; instead, their families moved to them, taking advantage of the Dutch government’s reunification laws and trading life in Fez, Rabat, or Ankara for the comparatively stable cities of Rotterdam, The Hague, or Amsterdam.

As these predominantly Muslim communities grew quickly in and around the country’s working-class neighborhoods, Dutch society was also undergoing rapid change during the era of bellbottoms, the Beatles, and the Vietnam War. A trend toward individualization and secularization spelled the end of a rigid system in which each religious community had minded its respective boundaries. In its place, a new type of “Dutch tolerance” emerged—one premised on gender equity, gay rights, free speech, and protections for cultural and ethnic minorities.

The last of these measures largely shielded the growing Dutch-Muslim communities from discrimination at the hands of those who believed Islam conflicted with the nation’s socially progressive turn.

“In the 1970s and 1980s, there was growing discontent of Muslim communities,” said Rath, noting that the decline in decent job prospects for the Turkish and Moroccan migrants only aggravated tensions. “The parties, however, had the principle that it was not appropriate to have a political fight about the presence of immigrants. You don’t use minorities to make a political point.”

By September 11, 2001, that principle had all but eroded.

For many Dutch, the terrorist attacks of 9/11 turned a latent unease toward Turkish and Moroccan communities into an open distrust of Islam. Lost on them was a bit of historical irony: The Twin Towers stood just north of where the Dutch had once erected a 12-foot-tall barrier—Wall Street, they called it—to demarcate the borders of tolerant New Amsterdam.

As the country turned a suspicious gaze on its Muslim communities, two of the most vocal peddlers of anti-Islam sentiment in the Netherlands—Pim Fortuyn and Theo Van Gogh—gained an increasingly receptive audience.

Fortuyn was an outspoken and openly gay political upstart. He described Islam as “backwards” and said that he would ban Muslim immigrants from entering the country if it were legally possible. Such statements accompanied his rapid ascent toward the top of Dutch politics, culminating with the formation of his own party, Pim Fortuyn List, in 2002.

Van Gogh—the great-grandson of Vincent Van Gogh’s brother—was a film director and fierce advocate of free speech. Together with Ayaan Hirsi Ali, a Somali-born Dutch politician who had denounced her Islamic faith, Van Gogh produced a 10-minute filmed titled Submission that depicted verses from the Quran on women’s bare bodies. The purpose, they said, was to highlight the issue of violence against women in many Islamic communities.

Through their respective paths, the two men actively hyped up a tension between the new brand of Dutch tolerance—one forged on socially progressive values—and the supposed backwardness of traditionalist Islam. Many in the Muslim community were quick to point out that the contrasts that the two men were drawing did not square with their own embrace of the openness of Dutch society.

Nonetheless, the gruesome deaths of Fortuyn and Van Gogh would give their messages a new sense of resonance among the Dutch.

An environmental and animal rights activist, fed up with Fortuyn’s exploitations of “the weak parts of society,” fired five bullets into the politician’s head and back just days before the 2002 general elections. This was the country’s first prominent political assassination since 1672, and it channeled immense anger toward the “naive cosmopolitan elite who had burdened the Netherlands with migration,” wrote Leo Lucassen, the director of Amsterdam’s International Institute of Social History, in The Journal of Modern History.

By all accounts, Van Gogh’s death in 2004 was even more startling. He was cycling to his Amsterdam office to finish a film on the life of Fortuyn when a 26-year-old Dutch-Moroccan, also on bicycle, shot him. As Van Gogh pleaded for his life, the attacker fired several more bullets, nearly decapitated him, and pinned a list of future victims to his body with the smaller of his two knives.

“The murder of Theo Van Gogh was a real turning point,” Lucassen told me. “He represented this new anti-religion, leftish ideology that was part of the 1960s and 1970s. Many people, even those from the left, would go on to argue that Muslims constitute a problem and a danger to the open society that the Netherlands is.”

Despite instant renunciation from Islamic leaders across the country, dozens of retaliatory arson attacks were attempted on Dutch mosques over the following weeks. “Live and let live,” like Pim Fortuyn and Theo Van Gogh, was dead.

At the time of Van Gogh’s murder, Geert Wilders, a known target of religious extremists, was granted round-the-clock police protection, which continues to this day.

“We should not import a retarded political Islamic society into our country,” Wilders said at the time. “The Netherlands has been too tolerant to intolerant people for too long.”

Though Wilders’s rhetoric has changed little since then, much else has. A Dutch-Moroccan mayor now presides over Rotterdam, the country’s second-largest city, where a progressive Islamic movement pledges to plant a tree each time a Dutch child is born. In The Hague, the Muslims for Progressive Values group unites members of the Islamic community to advocate for gender equality, freedom of speech, and the separation of church and state.                                                       

In many ways, Dutch Muslims appear to be at the forefront of the country’s push for an even more open-minded culture. Nonetheless, voters will head to the polls on March 15 divided over Islam’s place in Dutch society. The nation that enshrined religious pluralism in its founding document more than four centuries ago will test the limits of its much-heralded brand of tolerance.