Most people know George VI from the movie The King’s Speech. In it, he’s portrayed, largely accurately, as an earnest young man who overcame a crippling stutter with the help of an unconventional speech therapist and the unwavering support of his wife, Queen Elizabeth. But what are the other dimensions of this man, who died in 1952?

I learned about him as a father when I wrote my biography of his daughter, Queen Elizabeth II. But I had only fuzzy impressions of him as a loving husband and as a key figure during Britain’s fight for survival during World War II. A fuller view of the man took shape after Queen Elizabeth II granted me special access to the papers of George VI and his wife (later popularly known as the Queen Mum) in the Royal Archives, at Windsor Castle.

The diaries and letters were endlessly intriguing. I discovered that Lady Elizabeth Bowes-Lyon took 12 days to say yes after her future husband proposed for the third time, and that she spent 20 hours discussing the proposal with her ardent suitor as well as members of her close circle.

I also learned that when they were apart, Bertie (as George VI was known to friends and family) and Elizabeth wrote passionate letters to each other—his to “my own little darling one” and hers to “my dear darling.” Once when he was away stalking deer, she longed for his return “sunburnt, manly, & bronzed, bearing in your arms a haunch of venaison roti as a love offering to your spouse.” He replied that on arrival he expected “two lunches of course. One from you I hope darling in xxxxx etc etc & then an ordinary culinary one.”

Lady Elizabeth Bowes-Lyon took 12 days to say yes after her future husband proposed for the third time.

It was the seven years’ worth of diaries that George VI began writing on September 3, 1939, the first day of the Second World War, that yielded the most revelations. I came to appreciate not only his inquisitive mind, eager to absorb every detail, but also what his postwar Labour prime minister Clement Attlee described as “a good judgment and a sure instinct for what was really vital.” I was taken aback that the King could be bracingly assertive in private. Eight months after the start of the war, he told the minister of supply, Herbert Morrison, that his Labour Party was “partly to blame” for a shortage of armaments.

From the earliest days of the war, George VI regularly urged government officials to start postwar planning “to keep the spirit of the class mixing going.” His character assessments were sharp and sometimes biting. Soviet foreign minister Vyacheslav Molotov “looks like a small quiet man with a feeble voice but is really a tyrant.” The King showed humility in his private jottings after three weeks of war by admitting that “it is all an amazing puzzle.” Yet when faced with the failure to repel night bombing in London, he philosophically observed, “Science is always very slow in its methods. A man has to suffer many disappointments in its cause.”

His diary pages as well as his correspondences make clear that George VI had a close professional relationship with Winston Churchill, his prime minister from May 10, 1940, until the end of the European war. After an uneasy beginning—“Winston was not very talkative. Many of his important problems are difficult to extract from him”—the two men formed a mutually confiding bond. In 1943, the King told his mother, Queen Mary, that he had “studied the way in which his brain works. He tells me, more than people imagine, of his future plans & ideas & only airs them when the time is ripe to his colleagues & Chiefs of Staff.”

King George VI seldom read for pleasure, but he devoured countless reports on all manner of topics, in addition to his daily government boxes. At one point he lamented that “there is so much to read that there is no time for exercise. The reading matter is mostly lengthy, but very important, & it takes time to digest.” This model of diligence was imprinted on his daughter, the future queen, who would carry the same dutiful spirit for her 70 years on the throne.

Sally Bedell Smith’s George VI and Elizabeth: The Marriage That Saved the Monarchy is out now from Random House. She is also the author of several other royal biographies, including Elizabeth the Queen: The Woman Behind the Throne and Prince Charles: The Passions and Paradoxes of an Improbable Life, and the Substack “Royals Extra”