BRITISH TITLES - EARL
earl: holder of third highest rank of dignity in the peerage (2), called an earldom. The word derives from the Norse jarl or earl via the Anglo-Saxon eorl and is the sole peerage (2) rank not to have a latinate etymology. For a discussion of earls in the immediate pre-Conquest era and for two or three centuries afterwards, both in England and Scotland, see in particular the articles BUCHAN, NORTHUMBERLAND, RUTLAND and WINCHESTER. See also baron. The earl in the first few centuries after the Conquest, being still chiefly an official, was granted the 'third penny', or a slice of the revenue accruing from fees for cases brought in the county court of the shire over which he presided. From the later Middle Ages (see section on earlier creations of Earldom of March in WEMYSS and MARCH) the practice grew up of creating earldoms named after non-county entities, sometimes even families, e.g., Earl Ferrers or Earl Fortescue (note that in such cases the 'of is omitted).
An earl is referred to on paper or addressed on an envelope as 'The Earl (of) Blank' or 'The Rt Hon The Earl (of) Blank' in ascending order of formality, though a few such, notably the Earl of Mar and Kellie and the Earl of Scarbrough (qqv), prefer not to be addressed as 'The Rt Hon' at all on the grounds that the prefix more properly belongs to Privy Counsellors. In a social context 'Lord Blank' rather than 'The Earl (of) Blank' is considered preferable, though if the precise rank of the person referred to needs to be indicated the latter is the only way out. When addressing an earl in the second person 'Lord Blank' will suffice.
An earl's wife is called a countess, reflecting his notional equivalence in rank to the continental count. The same rules of address apply to her as to him, the word 'Countess' being substituted for 'Earl', and where divorced wives of earls are concerned the form of address is as with the divorced wives of a baron except that the words 'Countess (of)' replace 'Lady'. For an earl's eldest son see courtesy title. An earl's younger son(s) is/are addressed as for a baron's son. An earl's daughter is addressed as 'Lady Jane Binks', where 'Jane' is her forename and 'Binks' her surname, whether maiden or married. The practice has revived in recent years of adding a 'The' to 'Lady' when referring to her in the third person (also to 'Lord' where he is a duke's or marquess's younger son). It emanates from Court Circles but is deprecated by some members of the College of Arms. This is on the understandable grounds that it not only encroaches on the definite article which more properly pertains to a full peer but also implicitly places in an inferior position not just the eldest son and heir of an earl, marquess or duke since he has no 'The' to his courtesy title but a Prince or Princess who is not a child of the sovereign since they too are not accorded a 'The'. But the practice may well commend itself inasmuch as it presumbly has the sanction of the Crown.
Earldoms have for the last 200 years been traditionally granted to former Prime Ministers, though neither exclusively nor invariably so.