Not so, she will be Her Majesty Queen Catherine, just as Lady Elizabeth Bowes-Lyon became first Her Royal Highness the Duchess of York and finally Her Majesty Queen Elizabeth when her husband became King George VI
Ditto with King George V’s wife. Although she had her own title (Princess Mary of Teck), when she married, she dropped all her hereditary titles and became simply Princess (later Queen) Mary.
I heard speculation yesterday that after Catherine marries William, the Queen will probably grant her a title of her own. If not, she’d assume whatever title her husband receives after their marriage, like Sarah Ferguson received Duchess of York when Prince Andrew was given the title after their marriage.
Yep, George IV was really unhappy having to go to a rather uncooperative Parliament to divorce his wife, Caroline of Brunswick, and strip her of her title.
There’s only been one “king consort” in English history, Phillip II of Spain. Also the first two husbands of Mary I of Scotland were made “King of Scots” by virture of marriage.
Once she dies she reverts to her maiden name. This is why the Queen Mother is now properly refered to as “Lady Elizabeth Bowes-Lyon”, not “Queen Elizabeth, the Queen Mother”. And the only reason “Queen Mother” was even part of her style in the first place was to reduce confusion with her daughter. Mary of Teck was just “Queen Mary” after her husband died, not “Queen Mary, the Queen Mother”.
That would be completely without precedent in British history. Women automatically assume the feminine forms of their husbands’ titles (the reverse is not true). I do expect the media to start calling her “Princess Catherine/Kate” after the wedding, but that won’t be correct. Prince William will be granted the customary dukedom and she’ll be “HRH (Princess William) the Duchess of _____”.
On a somewhat related note, I just learned that in Japanese protocol, you don’t name the Emperor at all. He is officially refered to as only the Emperor. He’s only officially accorded a name after he dies in order to distinguish a past ruler like Emperor Showa or Emperor Taisho from the current Emperor.
Not officially; that’s just done so that they’re easier to tell apart in the books. She is still properly referred to as Her Majesty Queen Elizabeth, the Queen Mother, the last title she held. But if it’s necessary to distinguish her from the other queen consorts named Elizabeth, it’s convenient to call her Elizabeth Bowes-Lyon.
The only real change upon death that I can think of is that, for example in the case of the current monarch, she is correctly referred to as “Her Majesty the Queen,” the end, but upon dying will obviously no longer be called that, instead “Her Majesty Queen Elizabeth II.”
As for the OP, when William is His Majesty the King, Catherine will be Her Majesty the Queen. No special act of Parliament or other process is necessary to effect this. (In fact, there’s a constitutional argument that Camilla will legally be Queen, even though they have announced that she will use the style “Her Royal Highness the Princess Consort.”)
If William predeceases her, she will technically be Her Majesty the Queen Dowager (or would it be HM Queen Catherine, the Queen Dowager? I’m not sure). However, she might choose to use a different title, such as Queen Mother (if one of her children has ascended to the throne) or simply Queen Catherine (as Queen Mary did once her granddaughter had become Queen).