Get a brand-new perspective one of of the world's most-watched weddings

Credit: RR Auction/Splash News Online

More than 750 million people from around the world watched Princess Diana and Prince Charles say “I do” back in July 1981. But in the 34 years since then, many moments from the historic day have remained out of the public eye.

However, in 14 newly released pictures of the Prince and Princess of Wales’ July 29 wedding, a bit of the behind-the-scenes mystery has been lifted. In the candid photographs, Diana mingles with her young bridesmaids and prepares for the day’s official shots, while others show the family gathering at Buckingham Palace following the day’s festivities.

These pictures are just a few of the many taken by Lord Patrick Lichfield, a well-known British photographer who captured Charles and Diana’s day for the royal family. A nobleman himself (he was also the 5th Earl of Lichfield), he was the only photographer allowed “backstage” at the wedding.

Lichfield’s assistant developed the photos, and the “best” shots were placed into two albums and presented to the family. The outtakes – included these 14 photos up for auction – were given to Lichfield’s assistant, who has kept them for the past 34 years.

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The shots will be sold at auction by Boston-based house RR Auction next month. The minimum bid starts at just $300 for all 14 of the photographs, and typically, pictures would end up selling for $1,000 to $2,000, RR Auction Executive Vice President Bobby Livingston says. However, because of the public adoration for Princess Diana and the strong sentimental value, Livingston expects them to sell for a much higher sum. To put it in perspective, a pre-marriage photo of Diana and a male friend sold for $18,000 two years ago – and that was just one photo. This set includes seven glossy 10 x 8’s and another seven satin-finish 7 x 5’s.

“You can see the Queen watching the throng of people outside Buckingham Palace,” Livingston told PEOPLE. “It’s pretty spectacular.”

See all of the photos here.

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