The Middle Ages in the West saw the gradual dominance of the Roman rite over the local rites that had developed before the ninth and tenth centuries. Musically this entailed the spread of Gregorian chant. Later centuries saw the development of polyphony. In the late Middle Ages, the preaching service of Prone became the model for Reformed worship.
Although the Roman Mass, standardized by directives of the Council of Trent (1570), is technically a post-Reformation document, it is not an innovation but rather the summation of the medieval development of western Catholic worship. Consequently, the mass below is presented as part of the pre-Reformation liturgies as an example of ancient Catholic worship.