The liturgy of the Eucharist, the central service of the Roman Catholic Church. In the middle ages, the Mass was chanted and was one of the chief sources of music of that period that survive to the present. Many composers throughout European history have set the Mass to music from the early middle ages up through the present time. There are two major categories of the items of the Mass, the Proper, or the texts that are variable, and the Ordinary, or the fixed texts. The items of the Mass are as follows:Typical Ordinary Mass Typical Proper Mass Introit Kyrie eleison Kyrie eleison Gloria in excelsis Deo Gloria in excelsis Deo Gradual Alleluia Sequence Credo Credo Offertory Sanctus Sanctus Benedictus Benedictus Agnus Dei Agnus Dei Communion Ite missa est Ite missa est the major service of the Catholic church, commemorating Christ's sacrifice. The mass is divided into the proper (items with texts that change from day to day) and the ordinary (items with unchanging texts). A table of mass items is available. the solemn celebration of the roman catholic church, of the commemoration of the death and resurrection of Jesus Christ.<br><br>The fundamental property of a material relevant to sound transmission loss through that material. Generally, the more massive the material, the greater the sound transmission loss.