Prince Harry and Meghan Markle’s wedding venue at St. George’s Chapel in Windsor Castle held a surprising secret that no one noticed until recently.

Express journalist Alice Scarsi revealed that the chapel features several oriel windows. But one of the windows was turned into a royal pew in the 1510s. The hidden viewing room was initially called Catherine of Aragon’s Closet or Queen Catherine’s Closet because it was built by Henry VIII so that his wife, Catherine of Aragon, could watch some ceremonies.

The secret pew is simply a small window with a seat that is overlooking the choir, and it can be reached via a private entrance. At present, the secret room is referred to as the Closet for the Ladies or as the Royal Closet.

Queen Elizabeth II, Prince Philip, and their relatives who are younger than them have not climbed up the secret viewing room. The last monarch who used it was Queen Victoria. Decades ago, she watched her son and Princess Alexandra of Denmark tie the knot at the chapel.

“She insisted that this had been Albert’s wish, but insiders thought the Queen’s real reason for cheating London’s show-loving crowds of a Royal Wedding was the fact that in St George’s Chapel she could watch the ceremony unseen from Catherine of Aragon’s closet,” royal author Jane Ridley said.

Meanwhile, St. George’s Chapel is a very important location for members of the royal family. Several members of the British clan or those that have a connection with them tied the knot there. Ten British monarchs were also buried there, and some members of the royal family were also christened at the chapel.

Prince Harry, for instance, was baptized at St. George’s Chapel in Windsor Castle. And as such, he and his wife, Markle, decided to tie the knot there. Months after their wedding, Princess Eugenie and Jack Brooksbank also got married in the same venue on Oct. 12.

meghan marke, prince harry wedding
Prince Harry and Meghan Markle stand together in St George's Chapel at Windsor Castle for their wedding on May 19, 2018 in Windsor, England. The Duchess is rumored to have made an unusual request prior to their wedding day. Dominic Lipinski - WPA Pool/Getty Images