King Charles will be crowned at Westminster Abbey in a ceremony full of pomp, pageantry and solemn religious significance on Saturday, after he became monarch of the United Kingdom and 14 other realms on the death of his mother Queen Elizabeth in September.
For the best part of a thousand years, the kings and queens of England and Britain have been crowned at London's Westminster Abbey in a ceremony that has changed little throughout the centuries.
There have been 38 monarchs crowned at the abbey - Edward V, one of two young princes believed to have been murdered in the Tower of London in the 15th Century, and Edward VIII, who abdicated to marry American divorcee Wallis Simpson, were not crowned.
The coronation is not essential and no other monarchy across the globe has an event in the same style. But historian claim that it had persisted as a means to legitimise the monarch in a public way.
The coronation ceremony will begin at 1000 GMT following a procession from Buckingham Palace. It is set to be shorter than that for his mother 70 years ago at about two hours long compared to almost four hours.
A much larger procession will depart the Abbey, made up of armed forces from Britain and across the Commonwealth. The king and queen will travel in the gold state coach which was commissioned in 1760.
Sitting on the historic Coronation Chair, known as St Edward's chair and containing the Stone of Destiny, he will be anointed by the Archbishop of Canterbury with holy oil consecrated in Jerusalem.
It is the centre point of the ceremony and signals the conferment of God's grace on the sovereign. A new screen will provide "absolute privacy" during that moment.
The archbishop will then place the heavy St Edward's Crown upon his head. Charles will leave the Abbey wearing a different crown, the Imperial State Crown.
The public will be invited to swear allegiance to the monarch and to his heirs and successors.
Charles will wear robes of crimson and purple silk velvet at his May 6 coronation which were once worn by his grandfather King George VI at his own coronation in 1937.
Charles' second wife Camilla, whom he married in 2005, will also be separately crowned queen during the ceremony, and like her husband, anointed by the Archbishop of Canterbury.
She will be crowned using the crown of Queen Mary, commissioned and worn by the consort of King George V for the 1911 coronation. This is being reset with diamonds from Queen Elizabeth's personal jewellery collection as a tribute to her.
There will be 2,200 guests inside Westminster Abbey, far fewer than the 8,000 in attendance for Queen Elizabeth's coronation in 1953.
Among those will be the British royal family, including Charles' younger son Prince Harry but not his wife Meghan, or his two children, with the ceremony taking place on son Prince Archie's fourth birthday.
There will also be other foreign royals, officials and heads of states, with US first lady Jill Biden representing the United States and China's Vice President Han Zheng expected to attend on behalf of Beijing.
There will also be friends of Charles and Camilla present, representatives of charities and celebrities including Lionel Richie.