It’s been 44 years since Princess Diana and now-King Charles III exchanged vows in what became one of the most-watched royal weddings in history.

The couple were married on Wednesday, July 29, 1981, at St. Paul’s Cathedral in London. Diana was just 20 years old at the time, while Charles was 32.

An estimated 750 million viewers across 74 countries tuned in to witness the royal ceremony. During the service, Diana made a bold choice in her vows, choosing to leave out the traditional promise to “obey” her husband. Instead, she pledged to “love him, comfort him, honour and keep him, in sickness and in health.”

According to The New York Times, Diana and Charles had “very serious” conversations ahead of time about whether or not to include the word “obey,” ultimately deciding to leave it out.

A Slip of the Tongue at the Altar

Nerves were high during the ceremony, and one small mistake by Diana made headlines. While reciting her vows, she accidentally got Charles’ name wrong, calling him “Philip Charles Arthur George” instead of the correct “Charles Philip.”

This slip was noted in royal biographer Sally Beddell Smith’s book Prince Charles: The Passions and Paradoxes of an Improbable Life, and was also reported by the BBC at the time: “Wedding day nerves were apparent during the ceremony. Diana mixed up the Prince’s names, calling him Philip Charles Arthur George, rather than Charles Philip.”