JOHN YANG: Good evening, Iúm John Yang.

In London today a ceremony not seen in 70 years, the coronation of a British monarch.

There was all the pageantry befitting the occasion, dignitaries from around the world, including First Lady Jill Biden.

And in the streets, crowds clamoring for a glimpse of King Charles the third and Queen Camilla.

But as Malcolm Brabant reports there were also some protests.

MALCOLM BRABANT: This was supposed to be a scaled back coronation to reflect the financial strictures being endured by millions of Charles IIIús subjects.

But as the king finally fulfilled his destiny, the opulence on display was far grander than most Britons will have seen in their lifetimes.

Pomp and Circumstance are embedded in Britainús DNA, and enthral royalists, who braved the grim weather and glimed the procession route from Buckingham Palace to Westminster Abbey.

But Charles isnút as popular as his late mother the Queen.

Several anti-monarchists were arrested before the main event got underway.

Among them are members of a group called Republic, which has been staging únot my kingú protests since Charles ascended to the throne.

Their leader Graham Smith is seen here sitting on the ground surrounded by police officers.

We interviewed Smith before the coronation.

GRAHAM SMITH, Chief Executive, Republic: They misuse public money all the time for private use, they misuse public office to advance their own interests.

I think that if Charles were to stand in an election against other candidates in a free and fair election that he would lose and lose badly.

And yet here he is, as a head of state.

MALCOLM BRABANT: The police say some of those detained were held on suspicion of conspiracy to cause a disturbance, which was denied by Republic spokesman Harry Stratton.

HARRY STRATTON, Spokesman, Republic: Itús a completely peaceful demonstration.

The police without telling us why, without telling us where theyúre taking them, have arrested all rally organizers.

Britain is meant to be a democracy but Charles isnút treating it like one.

MALCOLM BRABANT: The arrests have been widely condemned by opposition, parliamentarians, and Human Rights Watch, which said this was something you would expect in Moscow, not London.

Absorbed by centuries old tradition, guests inside Westminster Abbey were unaware of the disturbances and in the most mystical or most bizarre element of the ceremony, ornate screens were erected while he was anointed with holy oil, symbolizing his spiritual status as head of the Church of England.

Historian Anna Whitelock.

ANNA WHITELOCK, Historian: It is entirely in Congress.

Now for some people, thatús his charm, that it represents this golden thread to through British history over centuries.

For others, it is both in Congress out of touch and also outrageous to be costing such a lot and also celebrating the kind of values which most people in modern Britain no longer subscribe to.

MALCOLM BRABANT: Britainús priceless crown jewels were at the heart of the ritual as King Charles was handed the Sword of Justice.

UNIDENTIFIED MALE: With this sword do justice, stop the growth of iniquity.

Protect the Holy Church of God and all people of goodwill.

MALCOLM BRABANT: The scepters of power and mercy were finally after being historyús longest ever serving heir to the throne, the crown was placed upon Charles head.

The ritual anointing of Queen Camilla was far more subdued.

As King Charles left Westminster Abbey to the national anthem, one of those carrying the train of his robe was the second in line to the throne.

His grandson, Prince George, whoús nine years old.

Perhaps he was wondering if he was looking at his own destiny.

Britainús gold State coach used in every coronation for nearly 200 years, carried the King and Queen back to Buckingham Palace, past cheering crowds.

JULIA WAIN, Coronation Attendee: Cold, wet, tired, feet hurt, but fantastic you know.

JOHN LOUDON, Coronation Attendee: I have a dear friend from the UK that lives in America.

She said sheúll never be a U.S. citizen, because sheús loyal to other crowds.

And I think itús kind of a beautiful thing.

MALCOLM BRABANT: Britain is the only European monarchy that stages coronations.

King Charles is 74.

His reign will not be a long one.

Itúll be up to his heir, Prince William, whether he continues this tradition.

For PBS "NewsHour Weekend", Iúm Malcolm Brabant.