After a lifetime as heir to his late mother Queen Elizabeth II, Charles, 74, became the oldest sovereign yet to be crowned at London’s Westminster Abbey.
At 12:02pm (11:02 GMT), Archbishop of Canterbury Justin Welby placed the solid-gold St Edward’s Crown on Charles’s head as a sacred and ancient symbol of the monarch’s authority.
Welby also crowned Charles’s wife, Queen Camilla, 75.
Cries of “God Save the King” rang out from the 2,300-member congregation, which included foreign royalty and political leaders.
US President Joe Biden, represented at the abbey by First Lady Jill Biden, tweeted his congratulations and paid tribute to the “enduring friendship” between the United States and Britain.
Returning to Buckingham Palace in the day’s second horse-drawn parade, the royal family appeared on the balcony to applause and more chants of approbation from tens of thousands of well-wishers braving a spring downpour.
Some had camped out for days. A ceremonial fly-past was scaled down due to the weather.
Not everyone joined in the celebration, however.
Shortly before the coronation, London police arrested dozens of protesters using new powers to crack down on direct action groups.
The anti-monarchy movement Republic – which wants an elected head of state – said six of its organisers were detained, while climate activists Just Stop Oil said 19 of its activists were held.
Nevertheless, dozens of Republic activists held aloft banners on the route of the procession route, declaring: “Not My King.”
As well as being the first coronation since that of Queen Elizabeth II in 1953, it was the first of a king since 1937. It was only the second to be televised and the first in colour and streamed online.