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An apology letter Prince Philip wrote to former U.S. President Richard Nixon in the 1960s has resurfaced this week, just ahead of the Duke of Edinburgh’s funeral Saturday.

Prince Philip wrote the letter in 1969, after making a faux pas at a White House dinner with the president. He told Mr. Nixon that after that evening, he had woken up “in a cold sweat,” realizing he had forgotten to make a toast to Mr. Nixon’s health. He said in comparison to others’ toasts, his was “very lame.”

“Dear Mr. President,” Prince Philip wrote in the letter, which was recently unearthed by the Richard Nixon Presidential Library. “I can’t begin to tell you how much I appreciated your very great kindness and hospitality at the White House. I was quite overwhelmed by the guests but delighted to meet such a distinguished company.”

In this image provided by The Richard Nixon Library & Museum, shows two sides of a letter that Prince Philip wrote to President Richard Nixon. 

The Richard Nixon Library & Museum via AP

“After the brilliance of the other speakers and yourself, I am afraid my contribution was very lame and that night I woke up in a cold sweat when I realized I had forgotten to propose your health! I do humbly apologize,” he wrote. 

Honored guests usually offer a toast to the president’s health and success during White House dinner, the Associated Press reports. This particular dinner had an all-male guest list, including comedian Bob Hope, business magnate Ross Perot and Nixon’s cabinet members.

Prince Philip told Nixon he was “quite overwhelmed by the guests but delighted to meet such a distinguished company.”

He also wrote about an interview he did with Barbara Walters in New York following the dinner.

“The weather in New York was horrible but otherwise all went well and I found Miss Walters particularly charming and intelligent. I hope we did a good piece,” he wrote. 

In this undated image provided by The Richard Nixon Library & Museum, Queen Elizabeth II and her husband Prince Philip talk with U.S. President Richard Nixon at Buckingham Palace in London.

The Richard Nixon Library & Museum via AP

While Philip’s toast gaffe may seem benign, he had been known to make more serious improprieties. He sometimes made deeply offensive remarks in public and his behavior was often deemed racist or sexist. For example, when visiting Aboriginal people in Australia with the queen, he asked: “Do you still throw spears at each other?” the AP reports.

He also once asked a female cadet instructor in the military if she worked at a strip club, according to the AP. 

On the popular Netflix series “The Crown,” which is fictional but chronicles the royals, Prince Philip is portrayed as slightly racy and bold, which resonated with many viewers in the U.K.