Princess Diana broke major royal protocol by refusing to say one word during wedding vows to King Charles 44 years ago

Princess Diana broke a major royal protocol during her wedding to King Charles back in 1981.

It has been 44 years since Princess Diana and Charles got married at St Paul's Cathedral on Wednesday 29 July.

At the time, Diana was aged 20 and Charles was 32, and the event was a huge deal in the UK and across much of the world.

750 million people in 74 countries tuned in to watch the display on TV, but Diana opted to miss out something that’s been standard for years.

Not only did she actually go on to say the wrong name at the altar, but she also declined to make a certain promise.

The late princess must have been nervous about the event, as in Sally Bedell Smith's book, Prince Charles: The Passions and Paradoxes of an Improbable Life, Smith explained that Diana referred to Charles as 'Philip Charles Arthur George', instead of 'Charles Philip'.

Princess Diana's wedding came with a broken tradition (Tim Graham Photo Library via Getty Images)

The BBC also reported: "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."

Meanwhile, Charles messed up when he said 'thy goods' instead of 'my worldly goods'.

We’ll call it even then.

Anyway, the tradition she broke might be something women cheer about today, as back in the 80s, it was customary for a royal wife to promise to ‘obey’ her husband.

Instead, Diana said that she would ‘love him, comfort him, honour and keep him, in sickness and in health’.

The New York Times reported that Charles and Diana had ‘very serious’ discussions about including the word obey at the ceremony with the Archbishop of Canterbury, Dr Robert Runcie.

In the end, they decided to leave it out.

This is because the NYT said they are ‘both believers in a slow but steady evolution of royal tradition’ and wanted to follow what modern English couples say instead.

Diana switched things up (Tim Graham Photo Library via Getty Images)

Dr Edward Carpenter, who was the Dean of Westminster Abbey, said in an interview that he was ‘absolutely delighted’ by the royal couple's choice to omit the word, as it’s ‘more Christian’.

''Marriage is the kind of relationship where there should be two equal partners, and if there is going to be a dominant partner, it won't be settled by this oath,'' the clergyman said. ''I think this is much more Christian.''

After the nuptials, a letter written by Diana two days after her wedding revealed how she felt about the event.

It was sent from Diana to Mark Simpson, a footman at Buckingham Palace.

Dated on July 31, she wrote to him: “I just wanted to thank you for all your kindness + patience you’ve showed towards me since I moved into B.P. My stay was made so much easier by your company as it was so terribly lonely + we had so many laughs for that I can’t thank you enough.”