London CNN — Britain’s King Charles III has been crowned in a once-in-a-generation royal event witnessed by hundreds of high-profile guests inside Westminster Abbey, as well as tens of thousands of well-wishers who gathered in central London despite the rain.

While Charles became King on the death of his mother, Queen Elizabeth II last September, the coronation on Saturday was the formal crowning of the monarch.

The service was a profoundly religious affair, reflecting the fact that aside from being head of state of the United Kingdom and 14 other countries, Charles is also the Supreme Governor of the Church of England.

In the most significant moment of the day, Archbishop of Canterbury Justin Welby placed the 360-year-old St. Edward’s Crown on Charles’ head. The spiritual leader of the Anglican Church then declared: “God Save the King.”

However, it has been modernized in certain key ways. The archbishop acknowledged the multiple faiths observed in the UK during the ceremony, saying the Church of England “will seek to foster an environment in which people of all faiths may live freely.”

The King took the Coronation Oath and became the first monarch to pray aloud at his coronation. In his prayer he asked to “be a blessing” to people “of every faith and conviction.”

In what is considered the most sacred part of the ceremony, the King was anointed with holy oil by the Archbishop of Canterbury. He was also presented with the coronation regalia, including the royal Robe and Stole, in what is known as the investiture part of the service.

Then, for the first time in coronation history, the archbishop invited the British public, as well as those from “other Realms,” to recite a pledge of allegiance to the newly crowned monarch and his “heirs and successors.”

Ahead of the event, some parts of the British media and public interpreted the invitation as a command, reporting that people had been “asked” and “called” to swear allegiance to the King. In the face of such criticism, the Church of England revised the text of the liturgy so that members of the public would be given a choice between saying simply “God save King Charles” or reciting the full pledge of allegiance.

The ceremony also included a reading from the Bible by UK Prime Minister Rishi Sunak and, in another coronation first, gospel music.

Once the King was crowned, his wife, Queen Camilla, was crowned in her own, shorter ceremony with Queen Mary’s Crown – marking the first time in recent history that a new crown wasn’t made specifically for this occasion.

Music played a central part in the proceedings, and five new compositions were commissioned for the main part of the service, including an anthem by Lloyd Webber, who is better known for West End musicals.

Charles and Camilla arrived at Westminster Abbey in a splendid coach drawn by six horses, accompanied by the Household Cavalry.

After the ceremony, the newly crowned King and Queen rode back to Buckingham Palace in a much larger parade, featuring 4,000 members of the armed forces, 250 horses and 19 military bands.

The pomp and pageantry concluded with a royal salute and the customary balcony appearance by the King and family members. They and the crowds below watched a flypast of military aircraft, slimmed down because of the poor weather.

Star-studded guest list

Some royal fans spent several days camping along the 1.3-mile (2km) route from Buckingham Palace, the British monarchy’s official London residence, to Westminster Abbey, the nation’s coronation church since 1066, in order to secure the best vantage point.

By early Saturday, the London Metropolitan Police Service announced that all viewing areas along the procession route were full and closed off to new arrivals.

The doors to the abbey opened just before 8 a.m. local time and quickly started to fill up. Many of the guests, including top British officials, faith leaders and international representatives, were expected to take their seats more than an hour before the ceremony started – reflecting the huge logistical challenges presented by an event attended by hundreds of VIPs.

The guest list was a Who’s Who of British public life and politics: All Sunak’s living predecessors as prime minister were there: Liz Truss, Boris Johnson, Theresa May, David Cameron, Gordon Brown, Tony Blair and John Major.

Mayor of London Sadiq Khan, UK opposition leader Keir Starmer and Chancellor of the Exchequer Jeremy Hunt were also in attendance.

Approximately 100 of heads of states from around the world and dozens of members of foreign royal families traveled to London for the occasion.

Canadian Prime Minister Justin Trudeau, Australian Prime Minister Anthony Albanese, European Commission President Ursula Von der Leyen and European Council President Charles Michel all attended the service, as did French President Emmanuel Macron.

US President Joe Biden did not travel to London. Instead US first lady Jill Biden led the American delegation, sitting next to Ukrainian first lady Olena Zelenska.

Plenty of celebrities also made an appearance, including singers Lionel Richie and Katy Perry, musician Nick Cave, actresses Emma Thompson, Maggie Smith, Joanna Lumley and Judi Dench, composer Andrew Lloyd Webber and broadcaster Stephen Fry.

Last to arrive, just before the King and Queen, were the most senior members of King Charles’ family, his siblings and children, including Prince Harry who traveled to the UK from the US without his wife, Meghan, the Duchess of Sussex and their two young children. Saturday is also Prince Archie’s 4th birthday.

Following the ceremony, Prince Harry did not appear on the Buckingham Palace balcony with his father and selected members of the family. CNN understands that the prince, who is no longer a working royal, did not receive an invitation to join the family for this moment.

The King’s younger brother Prince Andrew was also missing from the traditional balcony appearance. Andrew stepped back from royal duties in 2019 over his ties to disgraced financier and convicted pedophile Jeffrey Epstein. In January 2022, Andrew was stripped of his military titles and royal patronages after a judge ruled a sexual abuse civil lawsuit filed against him by Virginia Giuffre could proceed. The prince repeatedly denied any wrongdoing and the case was later settled out of court for an undisclosed sum.

Controversies ahead of the big day

Despite the splendor of the occasion, it has not been without controversy. Some have objected to millions of pounds of taxpayers’ money being spent on a lavish ceremony at a time when millions of Britons are suffering a severe cost-of-living crisis.

Security is by far the most costly element of large events and the Met said ahead of time that Saturday would be the largest one-day policing operation in decades, with more than 11,500 officers on duty in London.

The coronation has also attracted anti-monarchy demonstrations, with a small number of protesters arrested in central London on Saturday morning before the event began.

Republic, a campaign group that calls for the abolition of the monarchy, said the idea of the “homage of the people” was “offensive, tone deaf and a gesture that holds the people in contempt.”

Some eyebrows were also raised earlier this week when a controversial and widely criticized UK public order bill came into force.

Since the death of Queen Elizabeth II last year, there have been a number of instances of anti-monarchists turning up at royal engagements to voice their grievances against the institution.

The new rules, signed into law by the King on Tuesday, just days before the coronation, empower the police to take stronger action against peaceful protesters.

Republic said it was expecting between 1,500 and 2,000 people to join an anti-monarchy protest at Trafalgar Square, just south of the royal procession route. On Saturday morning, Republic said on Twitter that organizers of the protest had been arrested shortly after the demonstration started – including the group’s leader, Graham Smith.

The Metropolitan Police tweeted: “Earlier today we arrested four people in the area of St Martin’s Lane. They were held on suspicion of conspiracy to cause public nuisance.”

A further three people were arrested “on suspicion of possessing articles to cause criminal damage,” the force added. And “a number of arrests” have been made of people suspected of breaching the peace.

Despite the pomp of Saturday’s events, the King is facing significant challenges. A CNN poll has found that Britons are more likely to say their views of the monarchy have worsened than improved over the past decade.

The results of the survey, conducted for CNN by the polling company Savanta in March, show Charles’ heir Prince William is viewed with greater affection than his father.

Despite their cooler attitude towards the King, most Britons say they plan to take part in at least one event related to the coronation this weekend, the poll found, with many communities planning street parties and lunches.

Artists Perry, Richie and Take That will headline the “Coronation Concert” at Windsor Castle on Sunday evening and people have also been encouraged to use Monday, the final day of the long weekend, to volunteer in their communities.

CNN’s Lauren Said-Moorhouse, Max Foster, Catherine Nicholls, Lindsay Isaac and David Wilkinson contributed to this report.