The names assumed by Pseudo-Isidore, including Isidorus Mercator (conflated from the names of Isidore of Seville and Marius Mercator), Benedictus Levita and others are all pseudonyms. The forgeries originated in the archiepiscopal province of Reims, where they were first circulated and cited. Thanks to the research of Klaus Zechiel-Eckes, it is now also known that Pseudo-Isidore did important research at the library of the monastery of Corbie, in the Reims suffragan diocese of Amiens. Scholars disagree about whether all of the Pseudo-Isidorian forgeries are to be attributed to the same person or persons; or whether the False Capitularies of Benedictus Levita and the False Decretals of Isidorus Mercator represent separate but somehow related forgery enterprises. Zechiel-Eckes believed that the prominent theologian and abbot of Corbie, Paschasius Radbertus (abbot 842–847) was to be identified with Pseudo-Isidore; and that the earliest phase of work on the forgeries, amounting to a subset of the False Decretals, was completed in the later 830s. These theories once commanded wide support, but today they are increasingly disputed. Eric Knibbs has argued that older, traditional dating schemes, which placed the False Decretals in the 840s or early 850s, were essentially correct. Several decretal forgeries contain material that aims to justify Ebo in his episcopal translation to the bishopric at Hildesheim after 845. It has also emerged that the decretal forgeries incorporate many items from a mid-ninth-century Corbie manuscript of the works of Ennodius of Pavia, which would seem to preclude any dates for the decretal forgeries substantially before the 840s. Manuscripts Well over a hundred medieval manuscripts containing Pseudo-Isidorian material survive. The vast majority—around 100—carry copies of the False Decretals. They are traditionally divided into six different classes. Probably the most widely distributed version is the manuscript class that Paul Hinschius christened A1. Equally important, though much rarer, is the so-called A/B class, which was developed at Corbie, where Pseudo-Isidore also did his work. The B and C classes, available only in high-medieval codices, are derived from A/B. All of these classes contain the full collection of Isidorus Mercator in three parts. A fifth class, which Hinschius called A2, provides only the 60 decretal forgeries from Part I and an initial sequence of decretal forgeries from Part III; it is also known as the short version and is closely related to A1. Finally, Horst Furhmann identified a further class of manuscripts that he called the Cluny Version.