The Coronation service for King Charles and Camilla, the Queen consort, is under way in Westminster Abbey.
Around 2,200 people, including the Royal Family, celebrities, faith leaders and heads of state, are in attendance.
Thousands of people watched as a lavish procession made its way to the Abbey from Buckingham Palace.
King takes Coronation Oath
The Archbishop of Canterbury acknowledges the multiple faiths observed in the UK by saying the Church of England “will seek to foster an environment in which people of all faiths may live freely”.
Welby then administers the Coronation Oath – a legal requirement.
He asks King Charles to confirm that he will uphold the law and the Church of England during his reign.
The King places his hand on the Holy Gospel and pledges to “perform and keep” those promises.
Charles III also takes a second oath – the Accession Declaration Oath – stating that he is a “faithful Protestant”.
After the service, there will be a second, larger procession before a royal appearance on the Palace balcony.
Earlier, leading members of Republic, the anti-monarchy group, were among half a dozen people arrested near Trafalgar Square.