The monarch left the private letters inside her final red box

Queen Elizabeth II stands on the balcony during on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952.

Queen Elizabeth in June 2022. PHOTO: FRANK AUGSTEIN – WPA POOL/GETTY

Before her death, Queen Elizabeth wrote two private letters—one for her son, King Charles, and another for her top aide.

In an excerpt of royal biographer Robert Hardman’s book, The Making of a King: King Charles III and the Modern Monarchy (out Jan. 18), in the Daily Mail on Friday, the author describes how staff discovered two private letters that the Queen had left behind after her death on Sept. 8, 2022.

In the aftermath of the Queen’s death at Balmoral Castle, senior staff, including the monarch’s private secretary Sir Edward Young, were mapping out the days ahead when a footman brought them one of the Queen’s famous red boxes. The red box is the daily dispatch of papers from ministers around the U.K. There may also be documents and correspondence from representatives from the Commonwealth and other countries around the world.

“It was the last one that had gone up to the Queen before her death,” Hardman writes in the excerpt. “Like all red boxes, it had just two keys, one for the monarch and the other for her duty private secretary.”

Queen Elizabeth II and Prince Charles, Prince of Wales on the balcony of Buckingham Palace during the Platinum Jubilee Pageant on June 05, 2022

Prince Charles and Queen Elizabeth on June 5, 2022.CHRIS JACKSON/GETTY

Inside the box, Young found that the Queen had left a sealed letter to Prince Charles and a private letter to himself.

“We will probably never know what they said. However, it is clear enough that the Queen had known that the end was imminent and had planned accordingly. Were they final instructions or final farewells? Or both?” Hardman writes. “Elizabeth II had been completing her own last pieces of unfinished business.”

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The Making of a King: King Charles III and the Modern Monarchy

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The Queen also left behind her list of candidates to join the order of Merit — her final royal duty.

“The Queen had always taken it extremely seriously,” Hardman writes in Daily Mail’s excerpt. “The paperwork had gone up to her two days before so that she could go through the notes and tick her choices. Here it was, completed and returned for Sir Edward to make the necessary arrangements. It was the last document ever handled by Queen Elizabeth II. Even on her deathbed, there had been work to do. And she had done it.”