Shortly after the Paris reformation a greater than Eudes de Sully and a greater than Peter de Capua was stirred into action by the scandal of the Feast of Fools and the cognate _tripudia_. In 1207, Pope Innocent III issued a decretal to the archbishop and bishops of the province of Gnesen in Poland, in which he called attention to the introduction, especially during the Christmas feasts held by deacons, priests and sub-deacons, of _larvae_ or masks and _theatrales ludi_ into churches, and directed the discontinuance of the practice[991]. This decretal was included as part of the permanent canon law in the _Decretales_ of Gregory IX in 1234[992]. But some years before this it found support, so far as France was concerned, in a national council held at Paris by the legate Robert de Courcon in 1212, at which both regular and secular clergy were directed to abstain from the _festa follorum, ubi baculus accipitur_[993]. It was now time for other cathedral chapters besides that of Paris to set their houses in order, and good fortune has preserved to us a singular monument of the attempts which they made to do so. The so-called _Missel des Fous_ of Sens may be seen in the municipal library of that city[994]. It is enshrined in a Byzantine ivory diptych of much older date than itself[995]. It is not a missal at all. It is headed _Officium Circumcisionis in usum urbis Senonensis_, and is a choir-book containing the words and music of the _Propria_ or special chants used in the Hours and Mass at the feast[996]. Local tradition at Sens, as far back as the early sixteenth century, ascribed the compilation of this office to that very Petrus de Corbolio who was associated with Eudes de Sully in the Paris reformation[997]. Pierre de Corbeil, whom scholastics called _doctor opinatissimus_ and his epitaph _flos et honor cleri_, had a varied ecclesiastical career. As canon of Notre-Dame and reader in the Paris School of Theology he counted amongst his pupils one no less distinguished than the future Pope Innocent III himself. He became archdeacon of Evreux, coadjutor of Lincoln (a fact of some interest in connexion with the scanty traces of the Feast of Fools in England), bishop of Cambrai, and finally archbishop of Sens, where he died in 1222. There is really no reason to doubt his connexion with the _Officium_. The handwriting of the manuscript and the character of the music are consistent with a date early in the thirteenth century[998]. Elaborate and interpolated offices were then still in vogue, and the good bishop enjoyed some reputation for literature as well as for learning. He composed an office for the Assumption, and is even suspected of contributions in his youth to goliardic song[999]. It is unlikely that he actually wrote much of the text of the _Officium Circumcisionis_, very little of which is peculiar to Sens. But he may well have compiled or revised it for his own cathedral, with the intention of pruning the abuses of the