(F-MOf H.159). The tonary's function in chant transmission During the Carolingian reform the tonary played a key role in the organization and the transfer of Roman chant, which had to be sung by Frankish cantors according to Charlemagne's admonitio generalis after it was decreed in 789. The historical background was the Second Council of Nicaea in 787 during which Pope Adrian I accepted the Eastern Octoechos reform also for the Roman church. Fully notated neume manuscripts like the gradual and the antiphonary were written much later during the last decades of the 10th century, and the oral transmission of Gregorian chant is only testified by additions of neumes in sacramentaries. In the tonary the whole repertory of "Gregorian chant" was ordered according to its modal classification of the Octoechos. Michel Huglo developed in his dissertation the hypothesis about an original tonary which preceded the Metz tonary and the tonary of St. Riquier. It was probably a coincidence, that Pope Adrian I supported the Eastern Octoechos reform, but it is also evident that Carolingian diplomates present at the synode did not get interest in the communication of the modes by intonations called enechemata for the first time. Nevertheless, it was the difference between Greek and Latin chant sources and especially the particular function of the tonary in chant transmission, which led Peter Jeffery to the conclusion, that the huge repertoire of Roman chant was classified according to the Octoechos a posteriori. While early manuscripts of Greek chant always used modal signatures (even before neume notation was used), the fully notated graduals and antiphonaries of the first generation (10th century), written by Frankish cantors, report a lot of details about accentuation and ornamentation, but the melodic structure was remembered orally by tropes. Sometimes a tonary was attached to these manuscripts, and the cantors could use it by looking for the incipit of an antiphon in question (e.g. an introit to communio), in order to find the right psalmody according to the mode and the melodic ending of the antiphon, which was sung as a refrain during the recitation of the psalm. A Greek psaltes would sing a completely different melody according to the echos indicated by the modal signature, while Frankish cantors had to remember the melody of a certain Roman chant, before they communicated their idea of its mode and its psalmody in a tonary—for all the cantors who will follow