Why Wasn't Prince Philip a King?

• Buckingham Palace announced the death of Prince Philip, the Queen's husband, on Friday.
• Despite being the husband of a queen, Philip never became a king, the result of a longstanding royal tradition.
• Instead, Queen Elizabeth made her husband a Prince of the United Kingdom.

Prince Philip died Friday morning at the age of 99, Buckingham Palace announced. "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," the royal family said in a statement. "His Royal Highness passed away peacefully this morning at Windsor Castle."

Philip married the then Princess Elizabeth in 1947, five years before she became Queen, and was subsequently given the titles Duke of Edinburgh, Earl of Merioneth and Baron Greenwich, as Harper's Bazaar reports. He also had to renounce his former royal titles, Prince of Greece and Denmark, to marry Elizabeth. But he didn't become king upon his wife's ascension to the throne, nor did he immediately become Prince Philip after marrying a princess. Instead, the Queen made him a Prince of the United Kingdom by letters patent in 1957, their 10th anniversary year.

So why didn't Philip ever become king? It's down to royal convention, as i reports. The spouses of ruling British monarchs are known as consorts—but while the wives of kings typically receive the title "queen consort," the husbands of queens have never been king consorts. Queen Victoria created the title of prince consort for her husband Prince Albert, though Philip, the only male consort since Albert, was officially known as Prince of the United Kingdom instead. As Town & Country notes, the convention can be attributed to the ancient patriarchy of the royal family, in which kings must be rulers but queens can be solely symbolic figures.

So what can we expect for the spouses of future monarchs? Prince Charles' wife Camilla Parker Bowles—officially titled Camilla, Duchess of Cornwall—would customarily become queen consort when Charles became king. But ahead of their marriage in 2005, the palace announced that she would instead become princess consort upon Charles' coronation, perhaps to avoid further controversy after the breakdown of his marriage to Princess Diana. "It is intended that Mrs Parker Bowles should use the title HRH The Princess Consort when The Prince of Wales accedes to The Throne," Clarence House said in a statement, as Harper's Bazaar reports.

The royals have made no such statement regarding Kate Middleton, who married future king Prince William in 2011, as Town & Country reports. Thus, it's safe to assume for now that she'll receive the title of queen consort, and become known as Queen Catherine.