Prince Philip didn't bestow the title of 'King' when his wife, Elizabeth II became Queen in 1952.

It became a common question as to why he was not the King of England during Queen Elizabeth II’s 70-year reign - and it's down to a strict rule.

According to Reader's Digest, the British Parliamentary law makes the rule as to who is up next in the line of succession and what title the monarch's spouse will have.

The publication wrote that: "In terms of succession, the law looks only to blood, and not to gender. This rule makes the Royal Family tree sound complicated, but it’s actually easily explained.

"In terms of the spouses of royalty, however, that law treats men and women differently."

Explaining further, Reader's Digest added that, unlike a woman marrying into the Royal Family, a man "is not eligible to take the male form of his wife’s title"

Reader's Digest added: "In keeping with this, when Philip Mountbatten married then-Princess Elizabeth in 1947, he did not become prince. It wasn’t until 1957 that Queen Elizabeth bestowed the title of 'prince' on Philip by issuing a letters patent."

Previously speaking to Town and Country, royal historian Marlene Koenig said that this is the same for Princess Eugenie's husband, Jack Brooksbank.

Prince Philip was born on this day, June 10, in 1921. The royal died on April 9, 2021 - just two months before what would have been his 100th birthday.

Unlike Philip, Queen Camilla was granted a female-version title of Charles.

She was known as 'Queen Consort' after King Charles ascended the throne in September 2022, but the 'Consort' has since been largely dropped.

In February 2022, in her Accession Day message, the late Queen noted that she wanted her beloved daughter-in-law to be known as 'Queen Consort' - although it was previously thought she would have another title.

When she married Charles in 2005, it was thought that she would be called 'Princess Consort' when he became King.

Following Philip's death in 2021, Buckingham Palace released a statement.

The statement read: "It is with deep sorrow that Her Majesty The Queen announces the death of her beloved husband, His Royal Highness The Prince Philip, Duke of Edinburgh. His Royal Highness passed away peacefully this morning at Windsor Castle."

Less than a year and a half later, on September 8, 2022, the late Queen Elizabeth passed away in Balmoral aged 96.