William and Kate struggled to deal with Prince Philip's loss

It was difficult for Prince William and Kate Middleton to wrap their head around Prince Philip's death.

This was revealed in a 'Thank You' card mailed to constituents who sent the couple their condolences, “They will all miss their much-loved grandfather and great-grandfather, but your message has provided great comfort at this difficult time. 

The message was shared by the blog Gert’s Royal Replies, “The Duke and Duchess of Cambridge thank you for your kind words following the death of The Duke of Edinburgh. Their Royal Highnesses have been incredibly moved by the many thoughtful messages they have received in recent weeks.”

Gert’s Royal Replies said the card would “probably be a much more treasured memento from recipients than their usual photo card,” so it was “nice that they made this something that would last an extra long time.”

The Royal blogger said the card’s black border signifies “mourning” as per an “old Victorian-era tradition.

“While some royals use this black mourning edging, it’s not required that all royals use it,” they also noted on their website.