Newly surfaced letters written by the late Princess Diana to her personal secretary, Jane Parsons, revealed the Princess of Wales had a very strange honeymoon with then-husband Prince Charles, whom she would later divorced. In one of the letters, written Aug. 15, 1981, Diana wrote on the Royal Yacht Britannia: “The honeymoon was a perfect opportunity to catch up on sleep.” 

The letters were set to go up for auction in April. The auction house said it provided an “intimate glimpse into the marriage,” according to Vanity Fair.

Read: How Will Prince William Remember Princess Diana’s Death Anniversary? He And Kate Middleton Won’t Visit Paris Site

Diana and Charles, who married in 1981 but later separated in 1992 and divorced in 1996, were known for having the “wedding of the century.” A year after the divorce, Diana died in a car crash in Paris in August 1997.  

The letters also showed interactions between Diana, who was a mother at age 20, and her oldest son, Prince William. William, who was born in 1982, received 4,500 presents for his birth. As a result, Diana had to send out 24,000 thank-you notes, the letters revealed. 

Diana apparently didn't mind motherhood. In fact, she preferred not traveling too much since it kept her away from William. In one of the letters, she told Parsons about her experience when she returned home to William after a trip to Australia in 1983. 

“William recognised us instantly, which was a relief as sometimes children resent their parents leaving them!” she wrote. “It’s marvellous to be home again and hopefully we won’t have to do any more travelling this year… Wishful thinking!”

Most recently, Diana‘s former lover, James Hewitt, denied claims that Prince Harry, Diana's youngest son, was his. 

“No, I’m not,” Hewitt, 58, said on the Australian TV show “Sunday Night," earlier this month when asked by host Melissa Doyle if he was Harry's biological father. “It sells papers.”

He continued: “It’s worse for [Harry], probably, poor chap.”

Hewitt had a five-year affair with the late royal as her marriage to Charles crumbled.

Diana would go on to have a romantic relationship with Harrod's heir Dodi Al Fayed, who died with her in a car crash as paparazzi was chasing them in Paris.