The Sweet Nickname Princess Diana Had For Prince Philip

Princess Diana and Prince Philip had a special bond, and the older royal reportedly took his new daughter-in-law under his wing after she joined the royal family. "He tried to help her understand what it was like to marry into this institution," historian Andrew Roberts told Today. "This family, but also this institution. She was very thankful to him."

Letters between the two showed that Princess Diana had a deep affection for her father-in-law, sweetly referring to him in their correspondence as "Dearest Pa" (via Reuters).

While Diana had a stable relationship with her own father, her brother, Charles Spencer, told The Sunday Times (via Oprah Daily) that their "mother wasn't cut out for maternity." Their parents divorced when she was young, and her childhood was a rather lonely one. Diana's father died in 1992 (via The New York Times), but she at least still had a parental figure in Prince Philip.

Princess Diana's relationship with her father-in-law is a sharp contrast from the one she had with Queen Elizabeth. The two reportedly were not close, with biographer Andrew Morton writing in Diana: Her True Story (via Elle) that, while the queen was kind enough to her daughter-in-law, "it was governed by the fact that she was married to her older son and a future Monarch."

Morton wrote, "In the early days, Diana was quite simply terrified of her mother-in-law. She kept the formal obsequies — dropping a deep curtsy each time they met — but otherwise kept her distance."

It fell to Prince Philip to introduce Diana to royal life, explained royal biographer Ingrid Seward to Us Weekly, saying that he "looked after her" as he could relate to "what it's like to be the new boy on the block or the new girl on the block and suddenly come into this family with all their strange protocols and everything else."