The king had asked Welby to help broker a deal between his sons so that they could both attend the coronation, but it seems that there were some significant differences between the brothers that could not be resolved.
Prince Harry had recently published a book called 'Spare' which had caused a lot of controversy and made him hesitant to return to the UK.
Prince William, on the other hand, was not willing to let Harry attend the coronation due to concerns that he would steal the spotlight away from the event. The British media had reported that the Prince of Wales was worried about this as well.
There were some reports that Justin Welby had tried to talk to both Harry and William to help them reconcile, but it is not clear whether he was successful or not. Before agreeing to attend the coronation, Harry had reportedly had a heart-to-heart conversation with his father, which may have helped to ease some of the tension.
According to The Sun on Sunday, there was a "willingness and wanting to mend on both sides" after Harry's explosive revelations in his book and Netflix series. It was the first time Harry had seen his family since the memoir and six-part docu-series had shocked the royals.
While Harry had spoken with Charles about the invitation, he had not yet spoken to William. The report did not mention whether the Archbishop of Canterbury had talked to both brothers to try and end their differences. Buckingham Palace had also been in correspondence with Harry before he agreed to attend the coronation, but there were no significant talks other than those related to the couple's security at Westminster Abbey.
Sources cited in The Sun on Sunday said that the monarch was "happy" with Harry's decision to attend the coronation and "understanding" of Meghan staying behind with their children. They also suggested that Harry's attendance was a way to show support for his father.