A sacramentary is a liturgical book containing the texts intended for the celebrant (priest, bishop or pope) for the Mass. It was mainly used in the early Middle Ages and, from the 10th century, it was gradually replaced by the missal which contained, in addition to prayers, the songs and readings of the Mass. The sacramentary always contains elements related to the canon of the Mass, it may include variable texts. There are several types of sacramentaries, which are distinguished by their content and their internal composition: the Leonine Sacramentary, the Gelasian Sacramentary, the Old Gelasian type, the Eighth-Century Gelasien type, the Gregorian Sacramentary, or the type Hadrianum supplemented.