On 16 January 1373 when Humphrey, the last Bohun earl of Hereford, died, the inheritance of that ancient earldom must have been among the greatest in England. Although no accounts of the Bohun receiver-generals have survived, a valor of the half inherited by Anne, countess of Stafford, in 1412 estimated its income at ￡1,203 a year; as a third of the original estate was at that date still retained for dower, the total income must have amounted to about ￡3,600. This was not as much as the duke of Lancaster or the earl of Arundel could command in 1373, but it must have put Humphrey among the richest of the nobility. The fortune of the Bohuns derived principally from the lands of the earldom of Hereford, which they had possessed since 1200, augmented with those of the earldom of Essex, which they acquired through marriage with the Mandeville heiress in 1236, and the more recent acquisitions of the last earl's father, William earl of Northampton, a younger son who, as Edward III's boon companion, had profited from royal favour and the perquisites of war. Descended through Miles of Gloucester from a tenant in chief of William I, they were conscious that their blood derived through the female line from more than one of the heroes of ancient chivalry; they associated themselves, through their ancestors the counts of Boulogne, with the Knights of the Swan and the glorious exploits of the First Crusade. The story was told in the Historie de chivaler a cygne which was bequeathed by the earl's eldest daughter, Eleanor duchess of Gloucester, to her son Humphrey Plantagenet in 1399. From the time of Humphrey, the fourth earl (died 1322), if not before, the Bohuns had adopted the swan as their badge.

With such evident pride of ancestry it is not surprising that the last two earls and their co-heiresses should have had their psalters and books of hours, a remarkable number of which have survived, adorned with an unusual wealth of coats of arms, in shields or in clothing, and other items of family history.