PRINCESS DIANA According to The Associated Press, Diana referred to Prince Philip as “Dearest Pa” in letters from 1992

the duke offers to help try to patch up her marital problems.
“If invited, I will always do my utmost to help you and Charles to the best of my ability, but I am quite ready to concede that I have no talents as a marriage counselor!!!” he wrote, signing the letter “With fondest love, Pa.”

He sympathized with Diana’s plight, even going so far as to say that Charles “was silly to risk everything with Camilla.”
“We never dreamed that he might feel like leaving you for her. I cannot imagine anyone in their right mind leaving you for Camilla,” he added in one of the notes. “Such a prospect never entered our heads.”