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.
Originally, a coronation was a necessity for a monarch, but it is now a ceremonial event and no other monarchy across the globe has an event in the same style.
During the solemn ceremony, Charles will take an oath to uphold the law and the Church of England.
Sitting on the historic Coronation Chair, known as King Edward's chair and containing the Stone of Destiny, he will be anointed by the Archbishop of Canterbury, the spiritual leader of the worldwide Anglican Communion, with holy oil consecrated in Jerusalem.
Charles will also be presented with various hugely ornate golden orbs, scepters, swords and a ring, which all form part of the Crown Jewels and variously symbolize the monarch's power, authority and duties, and the power of God.
The Archbishop will then place the heavy St Edward's Crown, used in coronations for the last 350 years, upon his head.
It will not be just Charles who is crowned at the King's coronation ceremony on Saturday.
His wife Camilla will also go through a simpler, mini-coronation ceremony as queen.
In April, Buckingham Palace released details of the invitation to "The Coronation of Their Majesties King Charles III & Queen Camilla" which was sent out to the more than 2,000 coronation guests.
The description on the invitation was the first time that Charles's second wife has been officially referred to as "Queen Camilla."
Her status was only made clear in February last year when the late Queen Elizabeth said on the 70th anniversary of her accession to the throne that she wanted Camilla to be known as queen consort when Charles became king.
When Charles's first wife, the popular, glamorous Princess Diana, died aged 36 in a car crash in Paris in 1997, Camilla was depicted by the media as the most hated woman in Britain.
Charles and Diana separated in 1992 and divorced in 1996. Diana had blamed Camilla, often portrayed as staid and dowdy, for wrecking her marriage.
But Charles and Camilla married in 2005, and since then she has come to be recognised, albeit grudgingly by some, as a key member of the royal family, whose calming effect on her husband has helped him deal with his role.
Reuters