Nothing says “lack of research” faster than getting the titles wrong in a historical novel set in England. When a hero is referred to as Lord John Smythe one minute and as Lord Smythe the next, or he’s Sir John Smythe sometimes and Sir Smythe at other times, or the heroine is Lady Jane Reynolds at one time and Lady Reynolds at another — well, the one absolutely correct thing is that the writer doesn’t understand how titles work. And that always makes me — and other readers, I’m sure — wonder what else he or she got wrong, too.
There are five distinct levels to the British aristocracy, from most powerful to least::
Duke, Marquess, Earl, Viscount, Baron
Dukes, as the highest rank, are treated a bit differently from the lesser aristocracy. A duke (and his duchess) are addressed as “Your Grace” and referred to by those of lower rank, or people who are not intimately acquainted with them, as “His Grace” or “Her Grace” (e.g,, butler to housemaid: “His Grace would like his bath water now, Brunhilda.”) Rather than use “Your Grace” repeatedly in a conversation, however, a second reference when talking directly to the duke or duchess is likely to be “my lord” or “sir” (or “my lady” or “ma’am”).
Marquesses and their marchionesses, earls and their countesses, viscounts and their viscountesses, and barons and their ladies are addressed as “My lord” or “My lady,” sometimes a bit more casually as “milord” or “milady.” They’re referred to by those of lower rank, when talking about them rather than to them, as “His Lordship” and “Her Ladyship” or as “Lord Lastname” or “Lady Lastname.”
Dukes and marquesses are the “Duke of Somewhere” and the “Marquess of Something”, and they often use the title rather than their surnames. If James Bond had been the Duke of Bristol, he’d likely have signed his letters “Bristol” or “James Bristol” rather than using his birth name. Often the “something” or “somewhere” is a location that’s special to the person. A general who is given a title after he wins a great battle might adopt the location of the battle as his title.
Earls are often the “Earl of Something” as well. But earls sometimes adopt the family name as their title (for example, Princess Diana’s father, whose last name and title were both Spencer). In that case the “of” is left out and he’s known as “Earl Lastname.” Viscounts’ titles most often are the same as the last name, so again, the “of” is left out and he’s known as “Viscount Lastname.”
Children of the upper ranks receive varying honors. The oldest son of a duke, marquess, or earl uses one of his father’s secondary titles. Such a title is honorary, however, and carries no power.
Younger sons of a duke are “Lord Firstname Lastname.” They are never “Lord Lastname” but they can be referred to a bit more casually as “Lord Firstname.” Daughters of dukes and earls are “Lady Firstname Lastname.” They too can be more casually referred to as “Lady Firstname,” but never as “Lady Lastname.”
Younger sons of marquesses, earls, viscounts, and barons are simply Mister. Daughters of viscounts and barons are simply Miss.
All five ranks pass along the titles to the oldest son upon the death of the father (though there are modern-day exceptions to this rule, with some honors awarded for the life of the recipient only).
To go back to the original examples, Lord John Smythe is the younger son of a duke, but not a lord in his own right. He has essentially no powers; his is an honorary title only, based on his father’s rank. But Lord Smythe‘s title is entirely his own – he might be a marquess, an earl, a viscount, or a baron. Sir John Smythe would be a baronet (a knight or other lower-level honor awarded by the crown – not part of the aristocracy, but not exactly a commoner either). He can be called Sir John. But Sir Smythe doesn’t exist at all.
And the only way Lady Jane Reynolds and Lady Reynolds can be the same person is if she’s Lady Jane because her father had a high title and Lady Reynolds because she married Lord Reynolds — and even then she’s apt to prefer one title or the other.