Gregorian chants first came about in the early Middle Ages and were created for the services and the liturgy of the hours in which monks took part, in line with the rites of the Roman church. The melodies were not written down until the tenth century – in the form of conducting signs (Neumes) that were inserted above the Biblical texts. The chants to be heard on this CD mainly adhere to a code from the collegiate library of Einsiedeln Benedictine Abbey. What is known as Codex E 121 is in fact the oldest collection of Gregorian chants that has been completely annotated with neumes and originated in the second half of the tenth century (see facsimile excerpt on front cover).