island of Mont Saint-Michel were not the first, and there were a lot of later abbots who founded monasteries not only in Normandy, but also in the conquered territories of Northern, and Southern Italy, including Arabian Sicily, after the Norman Kingdom was established in the conquered Island. His fully notated tonaries were only copied in Brittany and Normandy, the Norman-Sicilian manuscripts rather imitated the libellum structure of the Aquitanian troper-sequentiaries, and only a few of them (E-Mn 288, F-Pn lat. 10508) have survived with a tonary using central French neume notation, in its style very close to the chant books of Cluny. The «Bibliothèque interuniversitaire de Médecin» still conserves the only manuscript with alphabetic notation which can be dated back to William's time. Thanks to the creative and innovative achievements of William as a cantor, reformer and architect, the local monasteries which he reformed, did not simply adapt to customs of the Cluniac reform, he contributed to the history of Norman chant his own local school which was as well inspired by elements of the local Norman tradition as by innovations of the Cluniac reform. The Aquitanian tonaries and the Winchester Troper The Aquitanian innovation can be traced back to a very prominent cantor within the Cluniac reforms: Adémar de Chabannes was educated by his uncle Roger de Chabannes at the Saint-Martial Abbey of Limoges and this school redacted the first chant manuscripts by additional modal signatures and a remarkable production of tonaries, which Michel Huglo called the "Saint-Martial group" or the monastic tonaries of Aquitaine. Adémar was the next generation after William of Volpiano and he was one of the first notators who used the diastematic form of Aquitanian neume notation, which had already been developed during the late 10th century. Another tonary corpus of the same region was Huglo's "Toulouse groupe" around the Gradual of the Saint-Étienne cathedral in Toulouse (GB-Lbl Ms. Harley 4951, F-Pn lat. 1118, and 776). All of these books of the local secular cathedral rite have a tonary libellum. The oldest one is the Troper Sequentiary of the Auch region (F-Pn lat. 1118) which was probably written in Limoges by the end of the 10th century. The intonation of the "plagi protus" (on folio 105 verso) is rather exposing the melos used in Old Roman chant of this tone (ranging between C and G), but the sequentiary (folio 114 recto) is opened by an