In ‘Geoffrey de Mandeville’ (pp. 357–9) I insisted on the necessity of keeping steadily in view the annual _firma_ of London and Middlesex, and showed that it was due in respect of the two jointly, and not, as has been alleged of Middlesex, apart from London. The further publication of the Pipe Rolls has enabled me to develop this position. While the citizens, as I showed, strenuously claimed to hold the city and county at ferm for £300, as in the charter of Henry I., the Crown no less persistently strove to exact a _firma_ of more than £500. The exact amount of the high _firma_ is first recorded at the change of shrievalty in 1169. The four outgoing sheriffs at Easter of that year account for £250 “blank” and £11 “numero,” as the half-year’s _firma_. This represents a total for the year of £500 “blank” and £22 “numero,” which is also precisely the sum accounted for in 1173–4.[476] The whole sum would thus amount to £547 “numero,” by the Exchequer system. But at Midsummer, 1174, there was a great and a sudden change. Brichtmer de Haverhelle and Peter Fitz Walter came into office not as sheriffs, but “ut custodes,” in the Exchequer phrase,[477] and at Michaelmas they accounted not “de firma,” but “de exitu firme.”[478] The sheriff farmed his county and answered for a fixed _firma_, as a tenant is responsible for his rent; the ‘custos,’ acting for the Crown, like a bailiff for a landowner, was responsible only for the actual proceeds (_exitus_). This distinction meets us even on the earliest Pipe Roll (1130).[479] It is obvious that, on the _firma_ system, the sheriff might make a profit or a loss, according as the sources of the ferm provided more or less than the rent for which he had to account. But the point on which I am anxious to insist is that the sources of his ferm were by no means so elastic as is alleged.[480] As Professor Maitland observes: The king’s rights are pecuniary rights; he is entitled to collect numerous small sums. Instead of these he may be willing to take a fixed sum every year, or, in other words, to let his rights to farm. He further describes these rights, in the case of a borough, as “the profits of the market and of the borough court,” together with “the king’s burgage rents.” Each of these sources, again, could be sub-farmed.[481] This being so, I cannot agree with Dr. Stubbs in holding that the sheriff was answerable to the Crown for a certain sum, and ... nothing was easier than to exact the whole of the legal sum from the rich burghers, and take for himself the profits of the shire; or to demand such sums as he pleased of either, without rendering any account.[482] For the sources of the ferm were well defined: they were limited to certain “rights.” The burgage rents were fixed; so, we believe, were the tolls; and the fines arising from the courts cannot have varied much. Outside these sources the sheriff had no right to “exact” anything from the burghers.