Courtesy Titles are titles allowed to certain near relations of peers by understood usage and the courtesy of society, but to which the users have no legal right. The subject of courtesy titles, though tolerably familiar in its general outline to persons resident in Britain, is complicated enough to be a frequent source of perplexity to Americans and foreigners, and may be thus explained: Dukes, marquises, earls, and even viscounts are often in possession of a number of titles belonging to an inferior grade in the peerage, which have in many cases been gradually accumulated by the ancestors of the peer in the course of his upward progress in the peerage. Some peers have as many as sixteen inferior titles—e.g. the Duke of Athole, who has one marquisate, four earldoms, three viscounties, and eight baronies. While in ordinary parlance a peer is known by his highest title (or titles, if he holds two of the same degree), his eldest son bears by courtesy one of his inferior titles. Thus the eldest son of the Duke of Devonshire is Marquis of Hartington; of the Duke of Buccleuch and Queensberry, Earl of Dalkeith; of the Marquis of Bute, Earl of Dumfries. There is no rule as to which inferior title should be assumed, a lower one being occasionally preferred to a higher; and the courtesy title may be different in one generation from another. The inferior title of a viscount who is also a baron is never borne as a courtesy title by his son; but a usage prevails among viscounts and barons (more properly 'lords') in the peerage of Scotland, of the eldest son designating himself 'master;' thus the eldest sons of Viscount Arbuthnot and Lord Lovat are known as the Master of Arbuthnot and Master of Lovat. Courtesy titles are allowed to the eldest sons of courtesy marquises and earls. Thus the eldest son of Earl Percy, himself eldest son of the Duke of Northumberland, is Lord Warkworth. There are various instances of titles borne by heirs-apparent or grandsons of peers which have no existence among the family honours, or are derived from them by some modifications. While Earl Nelson's inferior titles are Viscount Merton and Baron Nelson, his eldest son is known as Viscount Trafalgar. There are a few cases where, in consequence of the inferior title being identical with the higher one, the eldest son substitutes the family surname for the title. The Earl of Gosford, whose family surname is Acheson, is also Viscount Gosford and Baron Gosford; and his son adopts the courtesy style of Viscount Acheson. The holders of courtesy titles, not being legally peers, can sit in the House of Commons.
The younger sons of dukes and marquises have the courtesy title of 'Lord' prefixed to their Christian name and surname—e.g. Lord Charles William de la Poer Beresford, second son of the late Marquis of Waterford; and the daughters of dukes, marquises, and earls, have 'Lady' followed by their Christian name and surname, the surname being that of their husband if married, or his courtesy title if he be a courtesy peer. But if a lady enjoying such courtesy title marry a peer (not by courtesy), she only takes her husband's peerage title. Thus the fifth Duke of Buccleuch's second daughter, by her marriage with Donald Cameron of Lochiel, became Lady Margaret Elizabeth Cameron, while the same duke's eldest daughter is Marchioness of Lothian. Lady Emily Somerset, daughter of the Duke of Beaufort, on marrying Viscount Dupplin, eldest son of the Earl of Kinnoull, was known as Lady Emily Dupplin; but on her husband succeeding his father as Earl of Kinnoull, she became simply Countess of Kinnoull, this change of designation involving, curiously enough, a loss of precedence, inasmuch as the rank of a duke's daughter is higher than that of a countess. When, as often happens, a royal warrant is granted to the brothers and sisters of a peer whose father has never been in possession, giving them the precedence of the sons and daughters of a peer, they enjoy the corresponding courtesy titles. The title 'Honourable,' used by sons of earls, viscounts, and barons, and daughters of barons, belongs, not of courtesy, but of right, to them in common with all sons and daughters of peers.
The widow of a peer or a knight is allowed by courtesy to retain the title she acquired from her husband, notwithstanding a second marriage; the widow of a baronet is legally entitled to do so.
Along with courtesy titles may be ranked the appellations of the judges of the Court of Session in Scotland, who prefix 'Lord' either to their surname or to a territorial designation. These titles, though given in general society as well as on the bench, are not used in subscribing the judge's name, even to official papers. Hence Lord Medwyn's signature, 'J. H. Forbes,' and Lord Mure's, 'David Mure.' The wives of judges do not participate in their husband's titles. See ADDRESS, FORMS OF.