"I have been astonished and sometimes moved to tears by the fresh details and insights I have discovered in researching this story of family conflict," author Robert Lacey said of the book

By Maria Pasquini
June 20, 2020 01:15 PM
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Prince Harry and Prince William
Max Mumby/Indigo/Getty Images

Although Prince William and Prince Harry will always be brothers, their relationship has changed over the years.

In the forthcoming book Battle of Brothers: William and Harry — the Friendship and the Feuds, biographer Robert Lacey will “address the unique and complex relationship at the heart of the royal family’s recent woes,” according to a press release obtained by PEOPLE on Saturday.

Set to be released in October, the book will also put the two brother’s relationship into a historical context, examining how the “heir” and the “spare” dynamic has played out throughout history.

“Much reported on but little understood, Diana’s boys have lived under constant scrutiny since birth. Raised to be the closest of brothers, the last 18 months has seen a devastating breakdown of their once unbreakable bond,” reads the book’s synopsis. “With an unrivalled knowledge of court life and access to impeccable sources, Robert Lacey investigates the untold reality of the brothers’ relationship, explaining what happened when two sons were raised for vastly different futures and showing how the seeds of damage were sown as their parents’ marriage unravelled.”

The book also promises to address how the two brothers’ relationship has been impacted by their wives Kate Middleton and Meghan Markle, as well as shed more light on why Harry and Meghan decided to step back as senior royals and move to Los Angeles with their son Archie.

Battle of Brothers cover jacket

Throughout his work on the project, Lacey said he has been “astonished” by some of what he has uncovered.

“I have been astonished and sometimes moved to tears by the fresh details and insights I have discovered in researching this story of family conflict. It has been both enthralling and painful to trace this drama through the memories of close witnesses and some of the people most intimately involved,” he said in a press release.

Lacey, who is a historical consultant for Netflix's The Crown as well as the author of Majesty, a 1977 study of Queen Elizabeth, went on to explain that the book will also give readers an inside look at the British monarchy.

“These two brothers — once inseparable and now separated by much more than mere distance — have been acting out the contradictions that go back into their childhoods and even before that: into their parents’ ill-fated marriage,” he continued. "We have seen conflicts between heir and spare in every recent generation of the royal family — but nothing so profound as this.”

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The jacket cover includes a photo from the brothers' public reunion earlier this year on Commonwealth Day.

During their brief interaction, which appeared strained, after arriving at their seats, Harry and Meghan smiled and greeted William and Kate, who both offered brief hellos before taking their seats in front of the couple.

Prince William and Prince Harry
Eddie Mulholland/Getty

The rift between the siblings first emerged when William cautioned his younger brother against moving too fast in his relationship with Meghan.

Harry opened up about his relationship with his brother in last year’s ITV documentary Harry & Meghan: An African Journey, saying: “Inevitably stuff happens. But we’re brothers, we’ll always be brothers. We’re certainly on different paths at the moment.”

The brother’s relationship is “forever changed,” a source previously told PEOPLE in March. “They won’t get back to the way they were. Harry is looking straight ahead at his future with his family.”