At Eton College — the boarding school in the British countryside that has educated princes and 20 prime ministers — students wear tailcoats and white ties to classes. But some have worn waistcoats with the symbol of Black History Month underneath.

The students still sleep in ivy-covered stone dormitory buildings, some dating to the 18th century. Some of them have rainbow pride flags fluttering from them.

It’s an all boys school, but there also is a feminism society and a celebration of International Women’s Day.

“They’re on the right track,” said Alasdair Campbell, a 19-year-old recent graduate.

“Horrible,” said Felix Kirkby, 21, another of its alumni. “It’s destroying its reputation.”

Eton, which was founded in 1440 and covers grades seven to 12, has long been a symbol of British tradition and continuity, with its campus in the shadow of Windsor Castle, its elitist quirks and its expensive tuition.

But in a Britain that is more racially diverse, more open to questions about gender identity and economic inequality, and increasingly rejecting the aristocratic legacy of a white-dominated empire, Eton, too, is changing. Many students and alumni have welcomed its evolution. Some have not. Others argue that Eton needs an even more profound overhaul to remain relevant in present-day Britain.

Navigating the tightrope between past and present is Simon Henderson, who eight years ago became, at 39, the youngest headmaster in the school’s history.

Mr. Henderson, an Oxford graduate who taught history at Eton, has broadened access to scholarships — tuition is about 45,000 pounds, or $57,000, a year — and just last month, he announced an expansion of his previous initiative to partner with state schools in poorer areas of the north.

He has promoted discussions about masculinity, sexism and gender identity; celebrated Black and L.G.B.T.Q.+ history months; and appointed a “director of inclusion education” to address issues around race and sexuality. He sacked a professor who refused to take down a video he had posted on YouTube in which he had argued that patriarchy was partly caused by women’s choices because it benefits them.

Some of these moves have brought Mr. Henderson a nickname as “Trendy Hendy,” and criticism as a “woke” activist, while his firing of the professor ignited a debate over free speech on campus.

Mr. Henderson sees himself as a cautious modernizer, trying to both uphold Eton’s heritage and promote change.

“Eton is not immune from the broader society in which we sit,” said Mr. Henderson, wearing the school’s trademark white bow tie and cuff links with its coat of arms, in a recent interview in his office.

“There are moments in an institution’s path where it needs to step forward a bit more firmly,” he said. “And this is one of those moments.”

He dismissed accusations that he wants to dismantle the school’s traditions as a “myth,” but admitted, I know some people might feel the pace of change has been quick.”

Henry VI founded Eton as a school for children of the poor, but over time it became a bastion for the offspring of Britain’s rich and powerful, almost by birthright.

The Prince of Wales and his brother, Prince Harry, are alumni. George Orwell was a graduate, as was John Maynard Keynes; Percy Bysshe Shelley; and the adventurer Bear Grylls. The former prime minister Boris Johnson graduated from Eton as well; at age 16, he wrote in the school’s magazine that all parents should send a son to Eton because it will imbue him with “the most important thing, a sense of his own importance.”

Political leaders who followed an Eton College-Oxford University pipeline into Parliament have been accused of carrying into politics the entitlement and nonchalance they learned there, and for being out of touch with Britain’s reality.

As recently as 2011, an Eton admission test asked prospective students to imagine they were prime minister and to write a speech arguing that employing the army against violent protesters, and killing many of them, was “both necessary and moral.”

In recent years, Eton has admitted more sons of international money — fewer viscounts and more investment bankers — as well as more children from less affluent families, with the number of scholarships growing every year. Still, at least 75 percent of the students still pay the full fee.

The school has also become more academically selective and demanding, but in a more competitive educational environment, fewer Eton students are being admitted to Oxford or Cambridge than in past years. Mr. Henderson said some were now getting into Ivy League colleges in the United States instead.

Mr. Campbell, the recent graduate, said he supported Mr. Henderson’s efforts. He said that, for him, the conferences on issues of race, gender and privilege were eye-opening. It was time for the school’s elitist allure to go, he said.

“The closer Eton becomes to a normal school in terms of traditions the better light it’s going to have in the public’s eye,” Mr. Campbell said.

Yet even small, temporary decisions have created controversy.

Since 1857, Eton has kept a pack of beagles to use in hunting hares. But in 2004, hare hunting became illegal in Britain. The school kept the sport alive on campus by having the students train the beagles to follow an artificial animal scent, and then enter competitions.

Last spring, the keeper for the pack retired and the school did not find an immediate replacement. The dogs were temporarily moved off campus.

Hundreds of boys protested on campus, inspiring extensive coverage in the British press. The British conservative newspaper The Telegraph wrote that parents feared Eton’s hunting society “is being quietly axed through the backdoor by Eton’s ‘woke’ leadership.” Some parents, the newspaper wrote, even offered “to keep the pack together on their personal land estates.”

Mr. Kirkby, the 21-year-old alumnus and a child of academics who went to Eton on a scholarship, said the school should retain its quirky, aristocratic activities, like the requirement to wear tailcoats and some of its sports.

“It’s a powerful symbol of acceptance,” he said, as he sat at a cafe in Oxford, where he now studies. “For someone who grew up in a disadvantaged background to be able to hunt and shoot and fish.”

In his view, the approach Mr. Henderson is taking suggests an opposition to the very idea of Eton as an elite private school.

“Hendy,” he added, “is preparing the grounds for the school’s destruction.”

In 2020, the school erupted when Mr. Henderson fired Will Knowland, the teacher who had posted the video about patriarchy.

Some students defended the teacher, arguing that his firing would hurt Eton’s reputation as an institution where debate can be held freely. A letter asking for his reinstatement gathered thousands of signatures online; the students wrote that “the school is seeking to protect its new image as politically progressive at the expense of one of its own.”

The school said that it did not intend to shut down debate but that the sacking was a disciplinary matter since the teacher refused to take down the video after he was asked to. Mr. Knowland did not respond to requests for an interview but told British newspapers that free speech was critical to education.

Although many students said they appreciated the new sensibility Mr. Henderson has brought to the school, some say he hasn’t gone far enough, expressing a hope that the school would broaden scholarships more, as well as hire more nonwhite teachers, admit girls, and scrap the tailcoat altogether.

But Mr. Henderson said there were “no plans” to admit girls or get rid of the tailcoats. And the beagles are back on campus. Some of Eton’s traditions, he said, are “a physical, tangible connection to our past” and are “very, very valuable.”

At the end of the term last month at Eton, new students were in the town trying on cashmere uniform overcoats and shopping for color-coded socks for croquet, fencing or squash.

Caius Folkerts, 12, was enthusiastically doing his first fitting of an Eton tailcoat.

“They are not walking around in denim,” said his mother, Maie Folkerts, as she photographed her son in a tailcoat. “And hopefully they won’t ever.”