Crown Matrimonial
Appearance
The Crown Matrimonial is a legal concept and title used in most monarchical countries that gives the monarch's spouse the right to inherit the crown after the monarch's death, regardless of whether the spouse is in the direct line of succession.
For example, Queen Elizabeth, wife of King George VI of England and the Queen Mother of Elizabeth II and Princess Margaret, would have become queen after George VI's death if he had granted her the Crown Matrimonial. After her death, the title would have passed to her husband, the King's, next heir (namely, Elizabeth II).