for the menaion-part, and 3300 odes of the heirmologion. Chronological research of the books sticherarion and heirmologion did not only reveal an evolution of notation systems which were just invented for these chant books, they can be also studied with respect to the repertoire of heirmoi and of stichera idiomela. The earliest evolution of sticherarion and heirmologion notation was the explanation of the theta (Slav. fita), oxeia or diple which were simply set under a syllable, where a melisma was expected. These explanations were either written with Coislin (scriptoria of monasteries under administration of the Patriarchates Jerusalem and Alexandria) or with Chartres notation (scriptoria in Constantinople or on Mount Athos). Both notations went through different stages. Since the evolution of the Coislin system also aimed a reduction of signs in order to define the interval value by less signs in order to avoid a confusion with an earlier habit to use them, it was favoured in comparison with the more complex and stenographic Chartres notation by later scribes during the late 12th century. The standard round notation (also known as Middle Byzantine notation) combined signs of both Old Byzantine notation systems during the 13th century. Concerning the repertoire of unique compositions (stichera idiomela) and models of canon poetry (heirmoi), scribes increased their number between the 12th and 13th century. The Middle Byzantine redaction of the 14th century reduced this number within a standard repertoire and tried to unify the many variants, sometimes offering only a second variant notated in red ink. Since the 12th century also prosomoia (texts composed over well-known avtomela) had been increasingly written down with notation, so that a former local oral tradition to apply psalmody to the evening (Ps 140) and the Laud psalm (Ps 148) became finally visible in these books. Heirmologion The characteristic of these books is that their collection were over-regional. The probably oldest fully notated chant book is the heirmologion of the Great Lavra on Mount Athos (GR-AOml Ms. β 32) which has been written about the turn to the 11th century. With 312 folios it has much more canons than later redactions notated in Middle Byzantine notation. It was notated in archaic Chartres notation and was organised in canon order. Each canon within an echos section was numbered through and has detailed ascriptions concerning the feast and the author who was believed to have composed poetry and music of the heirmos: