The former Princess of Wales had “a quiet, stubborn belief in something as simple and elusive as love.”

• An unearthed letter from Princess Diana to a former school friend is coming up for auction in July.
• The letter was written on September 27, 1981, as Diana and Prince Charles remained on their honeymoon following their July 29 royal wedding that year.
• “Its [sic] wonderful being married,” Diana wrote. “I think its [sic] safe to say that after two months…!”

In an unearthed letter written from her 1981 honeymoon with Prince Charles, Princess Diana wrote of how “wonderful” married life was, per The Telegraph.

In the previously unpublished letter—written to a school friend named Katherine Hanbury—the Princess of Wales wrote that she enjoyed “endless sun” and “calm seas” as the couple cruised on the Royal Yacht Britannia. Diana and Hanbury were classmates at West Heath Girls’ School in Kent, and the letter was written as Charles and Diana’s honeymoon continued at Balmoral Castle.

Diana, then just 20 years old, wrote the letter on royal-crested paper and added, “We had a blissful honeymoon.” She continued that they were “now up in Scotland until the end of October, which is a big treat for us—I adore being outside all day and hate London!”

“Its [sic] wonderful being married,” she wrote. “I think its [sic] safe to say that after two months…!”

After their July 29, 1981 royal wedding, Charles and Diana sailed on the Royal Yacht Britannia for 12 days, cruising the Mediterranean before heading off to Balmoral. Of her new life in the royal family, Diana wrote, “Its [sic] a case of playing with grown ups!”

The letter is dated September 27 and is part of a collection of items being auctioned off by Hanbury. The items also include photos of Diana at school, like a photo of her sitting with a number of friends; the group includes actress Tilda Swinton. The collection will come up for auction in July, and its estimated value is between £4,000-£6,000.

The timing of the sale coincides with what would have been the 45th anniversary of Charles and Diana’s wedding.

“This intimate archive offers a rare glimpse of Diana, Princess of Wales before duty and fame had the final say,” said Albert Radford, books and manuscripts specialist at Gorringe’s Fine Art & Interiors, who is conducting the sale. “Through our client’s recollections from West Heath Girls’ School, Diana comes across as deeply unassuming and domestically minded—someone whose real ambition was simply to have a family and take pride in ordinary things.”

“She remembers Diana volunteering to clean the house of the headmistress, and it is memories like this and the collection that has come to light that present the real young Diana in a way that is completely at odds with the public persona that was created by others,” he continued. “She appears here as a young woman suspended between love and history—hopeful, unguarded, and not yet entirely claimed by the institution that would come to define her. In these small, fragile traces, innocence lingers—along with a quiet, stubborn belief in something as simple and elusive as love.”

Though Charles and Diana’s marriage has come to be known for strife and heartbreak—ultimately ending in separation in 1992 and divorce in 1996, one year before her death—royal biographer Ingrid Seward previously said that Diana wanted the world to see her love letters with Charles as proof that the love between them was genuine.

“Diana told me very shortly before she died that she wished people could see the love letters that she had from Charles,” Seward said, per The Times. “She really wanted people to know that she loved Charles, and he loved her. And I always remembered that. And she wanted the boys [Prince William and Prince Harry] to know that.”

“There was a period of great love between them,” Seward added.