SALISBURY, England » Arthur Pendragon, in his robes and sword, his queen by his side, stood in the long shadow of Salisbury’s magnificent cathedral, which has Britain’s tallest spire and the best preserved of the four surviving copies of Magna Carta. He was fulminating happily about the intrinsic rights of English men and women, prevented from free access to the other nearby magnificent place of worship, Stonehenge.

He stood in a bright evening sun Monday among a large crowd, and a lot of differently robed and bedecked Wiltshire County notables, too, watching a procession of huge puppets representing the county’s barons who signed Magna Carta, a copy of which has resided in Salisbury Cathedral for 800 years.

Salisbury then was enormously wealthy, a center of the wool trade, and now is a gorgeous example of the English shires that have helped keep the Conservative Party in power. It is where Edward Heath, the former Conservative prime minister, chose to live out his life, surrounded by memorabilia and fine art in a house within the cathedral close that he left to a foundation for public viewing.

Magna Carta has been praised and mythologized for limiting the absolute right of hereditary monarchs, establishing the rule of law and defending the rights of citizens against abuse. Of course, as Paul Smith, a chief guide at Salisbury Cathedral, notes, the rights involved were for the barons only, who were hardly ordinary citizens, and it was "quite a selfish document," soon annulled and then revised.

But the 800th anniversary of Magna Carta is a celebration, Mayor Andrew Roberts of Salisbury said, "not of a battle, but of an idea." The rights given by the document to the barons were extended, eventually and at least in principle, to all British men and women, and helped shape constitutional democracy elsewhere, not least in the United States.

King Arthur, a former biker born as John Rothwell, changed his name legally 30 years ago. He has campaigned for decades on behalf of Britain’s druids and pagans for access to Stonehenge, the still-mysterious circle of stones and burial mounds just outside Salisbury, begun about 3000 B.C., that is on a perfect axis for the summer and winter solstices.

With the summer solstice coming this weekend, Arthur will lead the ceremony there, at the Heel Stone, the most northeasterly stone where the sun comes up, he said, joined by "druids and pagans and bards and bands." Some 35,000 people are expected to join him, Stonehenge officials say, with a careful police presence, on one of the few days a year when admission fees are waived.

His partner, Kazz Smith, who is a florist when not reigning, complained about the high price of entry now that English Heritage, which operates Stonehenge, has significantly improved the site by covering over a road and building a parking lot and visitors center farther from the sacred stones.

The project, designed to restore Stonehenge to its landscape, cost 27 million pounds, about $43 million. But admission is 14.50 pounds for an adult, or 37.70 pounds for a family, and must be reserved in advance.

"People can’t afford it!" she said.

Arthur and Kazz are a living example of Richard Nixon’s sage advice to Heath, a noted yachtsman, inscribed to him in 1971 on a photograph of the former president at the wheel of a yacht.

"In our line of work," Nixon wrote, "it’s always good to have a second skill!"

Kate Davies, the general manager of Stonehenge, said that she knew Arthur well. He attends monthly meetings to plan for the solstice ceremonies, when the visitors center is shut, the site is free and celebrants are allowed within the stones, even with a small amount of alcohol, if they wish, "so long as there are no glass bottles."

The planning session, she said, is called "the round-table meeting – no connection to Arthur intended – open to druids and pagan representatives." She likes Arthur, she said, and found him a great advocate for celebrants to take public transportation to the site, since parking is limited.

"It’s a very different mood now from 20 or 30 years ago," she said, when celebrants clashed violently with the police and Arthur and his band were often arrested. "Of course the police have changed, too."

Among the stones on a beautiful late spring morning, Heather Sebire, the curator of Stonehenge, spoke of the circle and the burial grounds as a place of worship, even if precise Neolithic rites are unknown.

"We want to be careful not to write off our druid friends as some Victorian fantasy," she said. "But you feel something spiritual here. As an archaeologist, this is a ceremonial space, the equivalent of a cathedral. They gathered here, and I’m sure they were just as spiritual as we are, and perhaps more so. They were tuned into the elements, life was very hard, and the sun and the seasons mattered, and they revered their dead."

She remembered when President Barack Obama made a sudden visit last year, after a NATO summit meeting in Wales, with his entourage.

"They all ripped their ties off," Sebire said. "It was a beautiful evening, and Obama looked around and said, ‘I got it. If it weren’t a monument, I’d come just here to sit on a stone and meditate.’"

The dean of Salisbury Cathedral, the Very Rev. June Osborne, is the first female dean of one of Britain’s great medieval cathedrals, a vital center for worship.

"It’s very easy for people to go from metropolitan London to the northern industrial towns and miss the resonances of places like this," she said. In the early 13th century, "Salisbury was wealthy and an important academic center, and the Magna Carta here speaks to citizenship and about how people feel about being citizens."

There is a debate now, she said, about "whether we hold to universal values, or have some special ‘British values.’" So she has tried to use this anniversary of Magna Carta — including a specially commissioned cantata by Tarik O’Regan and Alice Goodman, and an unusual citizenship ceremony within the cathedral, with its large stained-glass window devoted to prisoners of conscience — "to allow the people of Salisbury and the cathedral to think of what it means to be a citizen."

Later that evening, as the huge baron puppets emerged from the cathedral itself, flanked by white horses, to the sound of a jazz saxophone and a modern, poetic riff on liberty, and fireworks split the night, Marie Thomas, who works in public relations for the cathedral, whispered to her husband, "It’s all a little pagan, isn’t it?"

Arthur Pendragon, king and senior druid, preparing for the solstice at Stonehenge, would have been pleased to hear that.

© 2015 The New York Times Company