MEMBERS OF THE NOBILITY went by more than one name: their family surnames and Christian names, but also their titles. For example, the younger brother of King Charles II had the family name Stuart and was baptized James, and so might be called James Stuart; but for most of his life he was the Duke of York, and so might also be referred to, in the third person anyway, as 'York' (but in the second person as 'Your Royal Highness'). Titles frequently changed during a person's lifetime, as it was common during this period for commoners to be ennobled, and nobles of lower rank to be promoted. And so not only might a person have several names at any one moment, but certain of those names might change as he acquired new titles through ennoblement, promotion, conquest, or (what might be considered a combination of all three) marriage.