Gregorio is not a completely independent program, but consists mainly of three components: The gabc syntax for writing Gregorian scores, a TeX package named GregorioTeX, which is responsible for the graphical output and a converter tool between those two. As such, Gregorio is included in TeX Live 2016.
Characteristics
Gregorio is written especially for Gregorian chant in square notation and does not cover modern European musical notation. Similar to LilyPond it does not provide a graphical user interface. The notation is done via simple text input. It follows the gabc-syntax, which is defined by the Gregorio Project for this purpose. The gregoriocommand line tool converts this gabc-file to a GregorioTeX file, which has to be included in a common TeX file. Such a file is necessary for a graphical output, e.g., in the PDF-format.
History
The Gregorio project started in 2006 at TELECOM Bretagne, a graduate engineering school in France. It was at first a student project lasting six months. When the project was done, Élie Roux decided to continue the project on his own and to develop it under GNU General Public License. At first, the goal of the project was just to provide the Benedictine AbbeySainte Madeleine in Le Barroux a graphical interface for the usage of a Gregorian font. Due to license issues, the project decided later to make and use its own font. At the end of 2006, a new developer, Olivier Berten, joined the project and created its OpusTeX component. OpusTeX was a LaTeX package with a similar goal like Gregorio but is now unmaintained and deprecated. During a three-month internship, starting in April 2008, at the Monastero di San Benedetto, in Norcia, Gregorio made considerable progress and its own output named GregorioTeX started to be usable. In following years Gregorio gained stability and popularity, strongly supported by the migration to GitHub in June 2014. Making contributions got much easier, therefore the development progress became faster. New feature like the adiastematic Saint Gall notation through nabc were implemented. Gregorio was adopted by many abbeys and large projects. The most prominent user may be the St. Peters's Abbey of Solesmes. In 2016 Gregorio should be integrated into TeX Live, which would make the installation process even more easy.
Example of Gregorio input files
For producing a score in the PDF format it is suitable to use two separate files — one gabc file and one TeX file. The musical notation is done in the gabc-file with the related gabc syntax. The TeX file could look like this :
The Church Music Association of America in different big projects, e.g. the "Simple English Propers", the "Parish Book of Psalms", the "Psalm-Tone Lenten Tracts"
Hymnarium OP, a Hymnary of the Dominicans of the Province of St. Joseph
the Mater Ecclesiae Abbey and the Praglia Abbey for the new "Antiphonale Monasticum" based on Fuglister's B-scheme, completely made with Gregorio and LuaLaTeX
"Liturgia Horarum in cantu gregoriano", a publication of the complete traditional Liturgy of the Hours, and "Ad Completorium", a printed excerpt of it, i.e. the compline for all days
and several other, smaller projects
Related projects
Other projects build and extend on Gregorio, for instance to make the usage more user friendly:
GregoBase, an extensive database of Gregorian scores, including nearly the entire Graduale Romanum and the Liber Usualis
Online tools, like online editors, Web interfaces or gabc-code generators for psalms, readings or hymns
