The adaptation of liturgical forms to extra-liturgical purposes; Mass; Requiem Mass--Stabat Mater; Magnificat; Te Deum--Musical masses and the Roman service--Bach: ‘B minor Mass’--Bach’s ‘Magnificat in D’; Pergolesi’s _Stabat Mater_; Handel’s Te Deums; Graun’s ‘Prague Te Deum’; Haydn’s church music--Mozart: the _Requiem_ and other masses--Cherubini: _Requiem_ and other masses; Schubert’s masses--Beethoven: _Missa Solemnis_; Weber’s masses--Berlioz: _Requiem_; _Te Deum_; Rossini’s _Stabat Mater_; Liszt: ‘Graner Mass’ and ‘Hungarian Coronation Mass’--Gounod: ‘St. Cecilia Mass’ and other masses; Dvořák: _Requiem_ and _Stabat Mater_; Verdi: ‘The Manzoni Requiem’--The masses of Rheinberger, Henschel and others. As polyphonic music developed with the expanding possibilities of the contrapuntal art and the increasing splendor of the Roman liturgical service, the old church composers seized upon certain portions of the liturgy as being especially adapted for musical exploitation and elaboration. The masters of the fifteenth and sixteenth century ecclesiastical vocal counterpoint made the musical settings of these parts of the holy office the object of their deepest consideration and lavished on them their utmost artistic skill and profundity. The parts of the holy office thus selected were those that were constant, invariable from day to day; they were six in number and in the following order: _Kyrie_ (in three parts, _Kyrie eleison!_ _Christe eleison!_ _Kyrie eleison!_), _Gloria_ (Doxology), _Credo_, _Sanctus_, _Benedictus_ and _Agnus Dei_. Since these were the principal musical portions of the eucharistic office sung by the choir, they came to be spoken of together as one composition, as Palestrina’s ‘Mass of Pope Marcellus,’ Gounod’s ‘St. Cecilia Mass,’ and so on. In all musical masses, ancient or modern, the same number and order of movements is preserved, since the holy office itself is universal and unchangeable. With the development of instrumental music in the seventeenth and eighteenth centuries, opportunities were offered for combining various instruments with the voices, and the mass with orchestral accompaniment arose. When sacred music finally broke loose from ecclesiastical control and came to be considered independent of the Church, composers took advantage of the great poetic suggestiveness of the missal text for constructing elaborate choral works with the combined resources of instruments and voices. While many of the modern masses here considered were written as liturgical music for actual church performance, many must be considered apart from any ecclesiastical use, as pure concert-music. The most prominent of these are probably Bach’s great ‘B minor Mass’ and Beethoven’s ‘Mass in D.’