The coronation of King Charles III and Queen Camilla

After the Recognition, the king was presented the Coronation Bible and took the Coronation Oath.

The Bible was presented by Iain Greenshields, moderator of the general assembly for the Church of Scotland, who sets the words of God – the Bible – as the "royal law" to govern with.

The presentation of the Bible dates back to the joint coronation of William III and Mary II in 1689, with the involvement of the moderator beginning in 1953, according to the Church of England's liturgy.

Before taking the Oath, Charles consented to its conditions, including fostering "an environment in which people of all faiths and beliefs may live freely." This addition to the service reflects the words of the late Queen, when she said the role of the church "is not to defend Anglicanism to the exclusion of other religions," but instead has a "duty to protect the free practice of all faiths in this country."

Then, Charles placed his hands on the Bible and promised to abide by the Oath as administered by the archbishop, swearing to govern the people of Great Britain and Northern Ireland, and the Commonwealth, while maintaining the laws of God.

Charles has been sovereign since the death of his mother, the late Queen Elizabeth II, but today he participates in the ceremonial rite of passage that accompanies being crowned king.

The coronation service starts with the Recognition, according to the Church of England's liturgy. For this symbolic moment, Charles will stand on a special platform built within Westminster Abbey called the Theatre, where he will turn to each of the four points of the compass to presents himself to the people, who will affirm and acknowledge him as the king.

Archbishop of Canterbury Justin Welby is the first of four representatives to make the declaration while facing the High Altar:

The congregation calls out, "God save King Charles," in response, recognizing him as the head of state.

The liturgy lists the other representatives as members of the oldest Order of Chivalry in England, the oldest Order of Chivalry in Scotland, and the Chair of the Victoria Cross & George Cross associations.

Justin Welby, the Archbishop of Canterbury, has begun the service.

"Dearly beloved, we are gathered to offer worship and praise to Almighty God; to celebrate the life of our nations; to pray for Charles, our King; to recognize and to give thanks for his life of service to this Nation, the Realms, and the Commonwealth; and to witness with joy his anointing and crowning, his being set apart and consecrated for the service of his people," Welby said.

"Let us dedicate ourselves alike, in body, mind, and spirit, to a renewed faith, a joyful hope, and a commitment to serve one another in love."

His introduction was followed by a rendition of "Kyrie eleison" -- the first time a Welsh-language piece of music has been performed at a coronation.

The Prince and Princess of Wales, have entered Westminster Abbey, following behind the King's procession – which is a slight deviation from the order of service.

William and Kate’s eldest child, Prince George is not walking with them. That is because he’s with the other pages of honor who will be attending King Charles and Queen Camilla throughout the service. There are eight pages of honor in all, four for the King and four for the Queen.

King Charles and Queen Camilla have entered the Abbey to the strains of “I was glad,” the stirring coronation anthem written by Hubert Parry for the coronation of King Edward VII in 1902 and sung at all coronations since then.

The choral music for today’s ceremony is performed by the Choir of Westminster Abbey, augmented by the Choir of His Majesty’s Chapel Royal, St. James’ Palace; choristers from Methodist College, Belfast; the Choir of Truro Cathedral and an octet from the Monteverdi Choir.

Parry incorporated a set of “vivats” – traditional Latin acclamations for the new monarch – into his piece, which must be rewritten for each coronation.

Today we hear the King’s Scholars of the prestigious Westminster School in London, singing Vivat Regina Camilla! Vivat Rex Carolus! (Long live Queen Camilla! Long live King Charles!).

The King and Queen have arrived at Westminster Abbey, with the start of the historic coronation ceremony just moments away.

After some will-they-won't-they speculation, Prince Harry accepted the invitation to his father's coronation, but he's without his wife, the Duchess of Sussex.

Meghan is back in California with the couple's two children as today is also Prince Archie's fourth birthday.

There's been heavy speculation in the lead-up to today's celebrations over how much involvement Harry will have and whether his presence means the family is moving on from the rift that saw the duke and duchess step back from their role as senior members of the royal family.

The palace previously said it wouldn't comment on whether the duke will appear on Buckingham Palace's famous balcony following the ceremony at Westminster Abbey. In fact, the palace is not confirming who will join the King on the balcony ahead of time at all. So that'll be a moment we'll have to wait for later.

CNN royal historian Kate Williams previously described Harry's appearance today as a "flying visit."

"[Prince Harry] is coming for this major event of his father's coronation but it's not going to be a family reunion. We're not going to see lots of big family meet-ups. Certainly, there has been damage done," she explains.

Williams adds that his presence is a "show of unity" but that we'll need to see what happens at the service.

As King Charles nears Westminster Abbey, several senior members of the royal family have entered the venue.

His siblings -- Princess Anne, Prince Edward and Prince Andrew -- have all taken their seats.

Earlier Queen Camilla’s family arrived at the Abbey, including her former husband Andrew Parker-Bowles and her daughter Laura Lopes and son Tom Parker-Bowles.

Prince Harry has arrived at the ceremony, among the first group of royals to enter the Abbey.

Harry is attending without his wife, Meghan, and their children, who have remained in the US.