History
Originally the book was called an antiphonale missarum ("Antiphonal of the Mass"). Graduals, like the later Cantatory, may have originally included only the responsorial items, the Gradual, Alleluia, and Tract.
In 1908 a revised edition of the Roman Gradual was published. In it Pope Pius X gave official approval to the work of the monastery of Solesmes, founded in the 1830s by Dom Guéranger, was done by Dom Pothier in restoring Gregorian chant to its purity by removing the alterations it had undergone, not really for the better, in the centuries immediately preceding. The work had involved much research and study.
That edition of the Roman Gradual was the basis also of a more general compilation of chants known as the Liber Usualis. This was not an official liturgical book, but it contained all the chants of the Roman Gradual, as well as other chants and hymns and instructions on the proper way to sing them.
In 1974, after the Second Vatican Council an edition of the Roman Gradual based on that of 1908 was issued. While the melodies remained unchanged, there was a relocation of pieces to fit the revised Roman Missal and calendar. Some chants were replaced by ancient ones rediscovered after 1908.
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