Modes of Reference
Before we leave the peers and deal with their relatives it will perhaps be useful to consider modes of reference when speaking to or writing to or of peers, since experience has shown that there is room for misconception even on this point.
A duke is the only peer who is always addressed by his rank, both in speaking to him, and in writing to him - that is, of course, assuming you are on sufficiently friendly terms with him to depart from more formal styles but nevertheless are not on Christian name terms. You would address him as "Duke" in conversation and say "Dear Duke" in writing to him.
But all other peers, from marquesses to barons, are normally addressed as "Lord So-and-so" in conversation and as "Dear Lord So-and-so" in a letter.
Even so eminent and careful a writer as the late Mr John Galsworthy makes one of his characters in The Forsythe Saga habitually address an English peer in conversation as "Marquess". This is unusual, to say the least. One addresses a foreign nobleman by his rank of marquis, count or baron, but it is not the customary practice in this country.
Even in speaking of other peers, as, for instance, at a meeting, or in writing to them, it is customary once one has given them their full rank - the Marquess of This, the Earl of That, or Viscount Another - to refer to them all as merely Lord This, Lord That, and Lord Another. The constant repetition of their full style is unnecessary.
A baron is always spoken of and referred to as Lord Blank. Only in the most formal state and legal documents is he referred to as Baron Blank. Thus the headline "Death of a Baron" is correct while "Death of Baron Blank" - which not infrequently occurs in newspapers - is incorrect from the point of view of conventional usage.
The only instance in which the rank of baron is used conventionally as a mode of address is when the holder is a female. This is in order to emphasise the fact that the lady is a peeress in her own right and not just the wife of a peer. Thus the elder daughter of the late Marquess Curzon of Kedleston, who succeeded to her father's barony of Ravensdale by special remainder, is referred to as Baroness Ravensdale, and not as Lady Ravensdale, as would be the case were she the wife of the holder of the title.
In such cases, incidentally, most holders sign themselves, as would a man, merely by their titles, and not with the title prefixed by the Christian name, as do the wives of peers.