Late in 1165 or early in 1166, King Henry II sent instructions via the shire courts requiring all who held land of him, that is to say the tenants-in-chief, to return the names of their subtenants and how many knights’ fees each of them held. The king's writ does not survive, but the returns reveal many of its details. The archbishop of York, Roger de Pont-l’Évêque, for instance, responded,

The returns were collected together in the exchequer, where they became known as the cartae baronum, the baron's charters. The king's interest was mainly financial. He was planning a levy or aid to finance the marriage of his daughter Matilda to the duke of Saxony, which had been discussed in 1165. That aid, when imposed in 1168, was calculated using the information that had been demanded in 1166. According to Neil Stacy's analysis in his new edition of the cartae baronum, in 1211 the original cartae remaining in the exchequer were copied out by Alexander of Swerford, a clerk of the exchequer, to support King John's proposed extension of scutage (the tax paid by tenants-in-chief in lieu of military service) to all knights’ fees, not just those of old feoffment. Swerford's copies survive in the Black Book of the Exchequer, now in The National Archives. Similar copies in the Red Book of the Exchequer were apparently transcribed in the 1230s from a lost copy of the returns in Black Book.

The cartae baronum have been edited twice before: by Thomas Hearne in his 1728 edition of the Black Book and by Hubert Hall from the Red Book in 1896. All who have used these works will welcome Neil Stacy's edition for its correction of previous inaccuracies and omissions, and above all for its index, which provides for the first time easy access to the texts. Stacy's edition allocates a Roman numeral to each carta and an Arabic numeral to each individual subtenant within it. Roger de Mowbray's carta, for example, is numbered ccxxxv: he is also found as a subtenant at cliv/13 and ccxxxiii/3. The index thus differentiates between tenants in chief and subtenants. Editorial notes are also clearly distinguished. A short biography of each tenant-in-chief is given, with a synopsis of the fee, but nothing is said about the subtenants. Stacy notices previous printings of each carta, although there are some significant omissions: for example, the cartae printed in translation in J. P. Yeatman's Feudal History of Derby (1886–1907). It would have been useful if those printings that include detailed notes on the subtenants and their holdings had been listed separately. A survey of the extensive unpublished notes on the cartae tenancies made by William Farrer (1861–1924), now scattered between various repositories, would have been another useful addition. The present edition's interest might have been increased by the provision of facsimiles of the two surviving original cartae, with examples of the hands of the scribes of the transcripts in Black Book and Red Book.

Stacy's choice of phrasing is sometimes infelicitous: “ticked more than one box” (xviii); “perhaps the catalyst which led to sleepless nights” (xix); “The son of Nigel de Bereville, Richard's little barony, centred at Beachampton, comprised” (146). There is also much unnecessary collation of Black Book with Red Book, particularly in view of the editor's contention that the latter was derived indirectly from the former. For example, the word fefamento in Black Book almost always appears as feffamento in Red Book, and so appears in the collation over and over again. These minor flaws should have been sorted out during the subediting process, but they are in any case only trifling distractions. While Thomas Hearne's and Hubert Hall's editions will continue to be used for their transcripts of other parts of Black Book and Red Book, Stacy's edition entirely supersedes them as far as the cartae of 1166 are concerned, and is a worthy addition to the publications of the Pipe Roll Society.