Royal historian Robert Lacey, author of the best-selling Battle of Brothers, exclusively writes this week's PEOPLE cover story, offering insights on the state of the monarchy, the Queen's legacy in action, and William and Kate's eye toward their future on the throne
"The prince takes his style from his royal grandmother, who intervened as the marriage of William's parents dissolved in 1995," Robert Lacey, a veteran royal historian and author of the best-selling book Battle of the Brothers, writes in an exclusive cover story for PEOPLE. "The 13-year-old was in a fragile place — alone and just starting boarding at the elite Eton College across the river from Windsor. Concerned for her grandson's emotional state, the Queen invited William up to join her when Eton boys went home for the weekend. "
Samir Hussein - Pool/WireImage Prince William and Queen Elizabeth
Lacey adds that Queen Elizabeth also modeled herself after her grandmother, Queen Mary, rather than her "too soft and cuddly" mother.
Lacey previously said that the lunches between the Queen and Prince William, who is second in line to the British throne, were Prince Philip's idea.
"Philip was crucial in helping coach William as a future King," he said. "It was Philip's idea to set up the lunches between William and his grandmother. When the time came for the Queen to talk business with William, Philip would quietly excuse himself because he didn't feel that the constitutional side of the Queen's job was something he wanted to interfere in."
Chris Jackson/WPA Pool/Getty Prince Philip and Prince William
Following the Queen's "never complain, never explain" strategy has earned Prince William favor with the public. Lacey sites a UK poll rating ranking Prince William to an 80% popularity rating, second only to the Queen at 85%.
BEN STANSALL/POOL/AFP via Getty Images Queen Elizabeth and Prince William
Following the death of Prince Philip, family scandals and growing cries to abolish the monarchy, Prince William's role within the royal family is more critical than ever.
"The British throne has survived beheading, exile and enough scandal to stock entire libraries. Now a new leader — William, not Charles — is paving the way forward," writes Lacey.
And the future king is doing so with a vivid example in mind: "At this crucial inflection point, William, 39, continues to model his leadership on the style he learned from his grandmother."