During the period known as the Middle Ages, a period which, for the purposes of this study, can be considered as comprising the centuries from the 9th to the 15th, a long series of condemnations and prohibitions of books were ordered by various ecclesiastical authorities. The brief list here given, as a link in the record of Church censorship, presents certain types or examples of the attempts made, in advance of any system of general Indexes, to supervise, control, and restrict the production and distribution of literature. _830–840._ During these years, measures were taken against Claudius, Bishop of Turin, and Agobardus, Archbishop of Lyons, on the ground of their heretical writings, but these last were not formally condemned. _849._ Gottschalk, a German monk, was, at the instance of Hincmar, Archbishop of Rheims, excommunicated and condemned to imprisonment for life, on the ground of his treatise against certain doctrines of St. Augustine. Gottschalk died in a dungeon about 869. The Index of 1559 places Claudius in the first class, in which he has the honour of being the earliest author. This entry is continued in the Index of 1564 and later. The name of Agobardus first finds place in the Index of 1605, and there only in connection with the _editio princeps_ of his works printed in 1605. The edition of 1666, and the later issues, failed to receive formal condemnation. Gottschalk’s treatise escaped the attention of the Index compilers. _1050._ _The Synod of Vercelli_ condemns the treatise by Berengar of Tours on the Lords Supper, and also the work by Ratramnus of Corbu (written some two centuries earlier) entitled _De Corpore et Sanguine Christi_.[22] The former book came under various later condemnations. _1059._ _A Synod at Rome_ compels Berengar himself to burn the thesis he had written in defence of his position. _1120._ _A Synod at Soissons_ compels Abelard to burn his treatise, _Introductio in Theologiam_. _1140._ _Innocent III_ orders the burning of the writings of Abelard and of Arnold of Brescia, and the confinement of the two authors in monasteries. _1148._ _A Synod at Rheims_ condemns four chapters of the Commentary by Gilbert de la Porrée on the treatise by Boethius, _de Trinitate_. Gilbert had proposed to make in the book such corrections as the pope might order; but the pope had refused to assume the task. Hefele speaks of this as the first known instance of an attempt to relieve a text from condemnation by means of expurgation. Gilbert does not find place in any of the official Indexes but is recorded by Lutzenburg.