A tonary is a liturgical book in the Western Christian Church which lists by incipit various items of Gregorian chant according to the Gregorian mode tonus of their melodies within the eight-mode system. Tonaries often include Office antiphons , the mode of which determines the recitation formula for the accompanying text the psalm tone if the antiphon is sung with a psalm, or canticle tone if the antiphon is sung with a canticle , but a tonary may also or instead list responsories or Mass chants not associated with formulaic recitation.
Although some tonaries are stand-alone works, they were frequently used as an appendix to other liturgical books such as antiphonaries , graduals , tropers , and prosers , and are often included in collections of musical treatises.
Tonaries were particularly important as part of the written transmission of plainchant, although they already changed the oral chant transmission of Frankish cantors entirely before musical notation was used systematically in fully notated chant books.
Each of them served as the finalis of two toni—the "authentic" ascending into the higher octave and the "plagal" one descending into the lower fourth. Aquitanian cantors usually used both names for each section.
The earliest tonaries, written during the 8th century, were very short and simple without any visible reference to psalmody. Tonaries of the 9th century already ordered a huge repertoire of psalmodic chant into sections of psalmtone endings, even if their melody was not indicated or indicated by later added neumes.
