Prince Harry and Prince William Reportedly Had Major Tension Way Before Meghan Markle

Prince Harry and Prince William's sibling rivalry reportedly goes way back, like a whole other decade back — according to a new book written by royal author Tina Brown.

While many believe the tension between the brothers began when Harry first got serious with Meghan Markle, Brown, who wrote The Palace Papers: Inside The House Of Windsor, claims the friction already existed. Per the Daily Mail, Brown wrote that Harry grew "angry" about 10 years ago when he felt William was "hogging the best briefs," and that the animosity escalated to a fever pitch after the Duke of Cambridge became patron of the Tusk Trust in 2015. A friend of the siblings said they had "Olympic rows" at the time, and that Harry was "very, very angry man."

In the book, the royal expert reported that Harry "vented" about William and his father, Prince Charles, to his then-girlfriend Cressida Bonas, who he dated from 2012 to 2014. Bonas allegedly persuaded Harry to see a therapist over his anger, as she found his complaints to be "tiresome."

"Cressida began to have serious worries about his mental health," Brown wrote. "It was she who first persuaded Harry to see a therapist." They split after two years of dating, and upon their breakup, Harry is said to have written Cressida a letter thanking her for helping him "address my demons and seek help."

Elsewhere, Brown wrote that shortly after Harry met Meghan, William was skeptical. "Every time his brother fell in love, it was an eruption of Vesuvius," Brown said. "'You do realize this is the fourth girl you've taken to Botswana,' he couldn't help remarking after Harry's starry-eyed account of the trip." His older brother was nervous at the rapid pace of their relationship. The author revealed, "Within months of Harry's involvement with Meghan, he reportedly told his father that his younger brother's obsession with her was 'like something I have never seen.'"

The bombshell book comes after it was reported that Harry wants to mend his relationship with William with the help of a moderator. "Harry, I'm told, suggested perhaps that they might get some sort of a mediator in on sort of these talks, to make some progress," royal expert Katie Nicholl told Entertainment Tonight earlier this week. "It was something that he had suggested to his father. He's made it very clear that he wants to sort things out. He wants things to be improved."

She continued, "I'm hearing that he wants to be over here for the queen's Platinum Jubilee celebrations in June. I think, possibly, that suggestion of a mediator is probably less the relationship with his father, because his father is open to wanting to sort things out. I would imagine it's more to do with his brother. I would imagine that that idea of wanting a mediator is probably more to do with him and William. His relationship, really, is at a bit of a crossroads. We have been told for many months now that they're not close at the moment. It has been very, very difficult."