“We all remember the days when Harry and William were joshing with one another, and it all seemed set for their relationship and the future—that Harry, as Diana always used to say, would be William’s wingman,” Diana’s biographer Andrew Morton told People. “It’s a great loss for the monarchy.”

From homelessness to young people, Prince William and Prince Harry have continued to support the causes championed by their late mother, Princess Diana, according to charity heads.