Spoilers ahead!

Ahead of Philip’s five-month tour aboard the Royal Yacht Britannia, the Queen hides a gift in her husband’s briefcase and stumbles upon a photo of a beautiful ballerina — Galina Ulanova. At the time, she doesn’t confront Philip about the photograph, but later on the episode, she attends a performance of Ulanova inGiselle, and the two women knowingly eye one another several times from across the stage.

Although Ulanova was a real dancer — the Russian-born dancer was known as one of the greatest ballerinas of the 20th century and performed the lead roles inSwan Lake,Romeo and JulietandGiselle— there is no evidence of a real-life affair between Ulanova andPrince Philip.

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Photo of Prince Philip in full military garb next to a professional shot of Russian dancer, Galina Ulanova.

“People have often said, ‘He must have been unfaithful,’ but there is no solid evidence for that,“Robert Lacey, the show’s historical consultant, told PEOPLE. “When you’ve seen the episodes, you get the feeling why people make that supposition. But there is no evidence for it.”

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Galina Ulanova performing onstage in a traditional ballerina costume.

“The Queen is depicted as suspecting, or believing, that something is wrong without being able to prove it,” Lacey continued. “And it provokes the worst period in their relationship without transgressing the bounds of what is proven.”

Elizabeth and Philip: A Royal Romance — The Real-Life Story BehindThe Crownis available now.

What the affair storyline does do, however, is set up the royal couple’s resolve to keep their marriage strong despite its challenges.

“The show reflects that they did something about it,” said Lacey, author ofThe Crown: The Official Companion. “You see how they created a new relationship, which leads to the second batch of children [Andrew and Edward].”

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Prince Philip and Queen Elizabeth smile at one another while walking arm-in-arm outside.

Show creator Peter Morgan said he wanted to depict the strains the royal marriage goes under on season 2.

“People are complicated, and I want to write a marriage in all its complexities, but at the same time, I think it’s a triumphant marriage,” Morgan told PEOPLE at the show’s London premiere. “They’re still married — and are happily married.”

Morgan continued, “She has always been nuts about him. She was nuts about him from the moment she met him, and I think that shows.”

source: people.com