 The Missa Salisburgensis is a polychoral composition which takes advantage of the multiple organs and various locations available for groups of singers and musicians to perform in Salzburg Cathedral, probably for the 1682 celebrations marking the 1100th anniversary of the founding of the Archbishopric of Salzburg.The vocal parts feature "in concerto" (soloists) and "in cappella" (the full choir) parts across the sixteen vocal lines.However, several times in the Mass, the composer "collapses" all the voices into simple four part harmony (SATB) and uses some of the instrumental groups, the cornetto and trombone choir, in particular, to play in unison with the human voices.