Various signs came to be used in different areas of the Empire, and collectively these early methods are known to modern scholars as palaeo-Byzantine notation. Because the neumes were not used to instruct the singer in how to perform the piece, but rather to remind him of details of a chant he already knew, they do not provide sufficient information to enable us to reconstruct the precise form of the melody with any certainty. It was only at a later date that the neumes used became more prescriptive, and that a modern transcription becomes possible.

Early notation in a Prophetologion (Add MS 11841) / British Library

The tradition of singing the psalms had existed since biblical times. In the Eastern church, as in the West, psalms were sung according to a system of modes, each of which combined particular notes of the scale in formulaic patterns at the start and end of each verse, with a recitation on a fixed tone between them. These formulae made it easier to memorise the chant, and to associate particular melodic patterns with particular words, or even moods.

Over the centuries an increasingly elaborate repertory of hymns was composed to complement the singing of the psalms. Tens of thousands of hymns are known today from surviving manuscripts, and they form an outstanding resource in terms of the inventiveness of their poetry as well as their theological content. The hymns take several different forms depending on their placement and function in the liturgy, and allow much greater scope for melodic elaboration than the simpler formulaic methods of singing the psalms. In the earliest manuscripts these hymns were written with no musical notation, except for occasional modal designations in the margins.

Hymns from Sinai: Modal designations appear in the margins of this early manuscript containing hymns (Add MS 26113) / British Library

Middle Byzantine notation From the 12th century, a much more detailed system of notation came to be widely used throughout the Byzantine church. Because the hymn melodies were increasingly elaborate and were much more varied than the psalm formulae, the notation had to be capable of recording precise details of the movement of pitch as well as nuances of articulation and ornamentation. The resultant system, known today as the Middle Byzantine Notation, drew upon and expanded the range of neumes found in the palaeo-Byzantine schemes so that every detail of the melody could be recorded on the page.

Most of the books in which this detailed notation is found are small in format, and it is not common for them to show explicit evidence of use in performance. It seems likely that the books were intended more for reference purposes, as well as for instructing singers in how to perform the chants. For this reason, the chants are often presented in the order of their modes, so that melodically-similar hymns are found near one another, rather than in the order of the liturgical year.