King Charles signed the declaration which officially makes him the new Monarch using ink from a pot gifted to him by his sons, Prince William and Prince Harry.
Charles was officially declared Head of State at a meeting of the Accession Council at St James's Palace in London, attended by privy councillors including Liz Truss and six former Prime Ministers. Queen Consort Camilla was also in attendance, along with Prince William who was yesterday made the new Prince of Wales.
During the meeting, which was televised for the first time in history, Charles had to sign two copies of the declaration. He did so using a fountain pen with black ink from a small silver pot. Camilla and William also used the pot when they signed the documents.
The touching gesture comes after of months of tension between Harry and his father and brother. In his bombshell interview with Oprah Winfrey, he accused Charles of cutting him off financially and said William was "trapped".
The new King signed the declaration Charles R, as is traditional for the Monarch.
The tradition of signing with the initial R goes back centuries for English monarchs and is used to designater authority of the sovereign. It goes back as far as Henry I, who ruled in the early 12th century, and is how all official documents and formal letters are signed.
As King, the R stands for rex in Latin. When the Queen used it, it stood for regina.
More than 200 privy councillors – a group of mostly senior politicians past and present, some members of the monarchy and other national figures – were present to hear the Clerk of the Council read the Accession Proclamation.
The new monarch became King the moment his mother died, but an Accession Council must be convened following the death of a sovereign – usually within 24 hours.
Paying tribute to his late mother during his accession speech, saying: "My mother gave an example of lifelong love and of selfless service. “My mother’s reign was unequalled in its duration, its dedication and its devotion. “Even as we grieve, we give thanks for this most faithful life."
King Charles' speech in full
My Lords, Ladies, and Gentlemen.
It is my most sorrowful duty to announce to you the death of my beloved Mother, The Queen.
I know how deeply you, the entire Nation – and I think I may say the whole world – sympathise with me in the irreparable loss we have all suffered.
It is the greatest consolation to me to know of the sympathy expressed by so many to my Sister and Brothers and that such overwhelming affection and support should be extended to our whole family in our loss.
To all of us as a family, as to this kingdom and the wider family of nations of which it is a part, my Mother gave an example of lifelong love and of selfless service.
My Mother’s reign was unequalled in its duration, its dedication and its devotion. Even as we grieve, we give thanks for this most faithful life.
I am deeply aware of this great inheritance and of the duties and heavy responsibilities of Sovereignty which have now passed to me. In taking up these responsibilities, I shall strive to follow the inspiring example I have been set in upholding constitutional government and to seek the peace, harmony and prosperity of the peoples of these Islands and of the Commonwealth Realms and Territories throughout the world.
In this purpose, I know that I shall be upheld by the affection and loyalty of the peoples whose Sovereign I have been called upon to be, and that in the discharge of these duties I will be guided by the counsel of their elected parliaments. In all this, I am profoundly encouraged by the constant support of my beloved wife.
I take this opportunity to confirm my willingness and intention to continue the tradition of surrendering the hereditary revenues, including the Crown Estate, to My Government for the benefit of all, in return for the Sovereign Grant, which supports My official duties as Head of State and Head of Nation.
And in carrying out the heavy task that has been laid upon me, and to which I now dedicate what remains to me of my life, I pray for the guidance and help of Almighty God.