King Charles had an aggressive reaction to his brother when it came down to his eldest son, Prince William.

Prince Edward, who is now the Duke of Edinburgh and a working royal in his brother’s monarchy, once caused his brother to rage over a stunt he pulled, while William was still in university in Scotland.

Before William started his university, privacy agreements were put in place with the press, in a bid to protect the royal and his friends while studying. This meant paparazzi shots would not be published.

Edward ran a two-man film crew from Ardent and in September 2001. However, when a story was published by Ardent, Charles went “ballistic” and William was “furious.”

Royal author Robert Jobson recalled the incident in his 2006 book in which he detailed that the now-king Charles was “too was angry with Edward, and felt he needed to make a choice between his royal and professional responsibilities.”

Charles “berated his youngest sibling, furiously demanding from the Queen that Edward be made to choose once and for all between his public duties and his television company — itself many believed little more than a vanity project dependent on Edward’s title for what little success it had.”