The above descent is not based upon the evidence of the _Monasticon_ alone, but is incidentally recited in those royal charters on which my story is so largely based. It is therefore beyond dispute. But though there is no pedigree of the period clearer or better established, it has formed the subject of an amazing blunder, so gross as to be scarcely credible. Madox had shown, in his _History of the Exchequer_ (ii. 400), that Geoffrey "Fitz Piers" (Earl of Essex from 1199 to 1213) was Sheriff of Essex and Herts in 1192-94 (4 & 5 Ric. I.). Now Geoffrey, the son of Geoffrey "Fitz Piers," assuming the surname of "De Mandeville," became his successor in the earldom of Essex, which he held from 1213 to 1216. The noble and learned authors of the _Lords' Reports on the Dignity of a Peer_ began by confusing this Geoffrey with his namesake the earl of 1141, and bodily transferring to the latter the whole parentage of the former. Thus they evolved the startling discovery that the father of our Geoffrey, the earl of 1141, "was Geoffrey Fitz Peter [_i.e._ the earl of 1199-1213], and probably was son of Peter, the sheriff at the time of the Survey."[105] But not content even with this, they transferred the shrievalty of Geoffrey "Fitz Piers" from 1192-94 (_vide supra_)[106] to a date earlier than the grant to Geoffrey de Mandeville (his supposed son) in 1141. Now, during that shrievalty the Earls "of Clare" enjoyed the _tertius denarius_ of the county of Hertford. Thus their lordships were enabled to produce the further discovery that the Earls "of Clare" enjoyed it before the date of this grant (1141), that is to say, "either before or early in the reign of King Stephen."[107] The authority of these Reports has been so widely recognized that we cannot wonder at Courthope stating in his _Historic Peerage of England_ (p. 248) that "Richard de Clare ... was Earl of Hertford, and possessed of the third penny of that county, before or early in the reign of King Stephen." Courthope has in turn misled Dr. Stubbs,[108] and Mr. Doyle has now followed suit, stating that Richard de Clare was "created Earl of Hertford (about) 1136."[109] It is therefore something to have traced this error to its original source in the _Lords' Reports_. The first mention, it would seem, of the subject of this study is to be found in the Pipe-Roll of 1130, where we read— "Gaufridus de Mandeville reddit compotum de Dccclxvj_li._ et xiii_s._ et iiij_d._ pro terra patris sui. In thesauro cxxxiii_li._ et vi_s._ et viii_d._ "Et debet Dcc et xxxiij_li._ et vj_s._ et viij_d._" (p. 55).