Several masses with large orchestration attest to the outstanding compositional skills of the Salzburg master Heinrich Ignaz Franz Biber (1644-1704) in coping with large ensembles. As usual in Salzburg, Biber expects polychoral performances. The church music at the Salzburg cathedral drew its orientation from the performance practice in Venice. The Missa Alleluia was probably composed after 1690 and certainly before 1698, because a manuscript was made in Kremsmunster that year. The original score and sheets from Salzburg are lost. Excellent copies have been preserved at the Upper Austrian abbey at Kremsmunster: they serve as a basis for the present recording. Biber has fully exploited the possibilities of Baroque Instrumentation in the Missa Alleluia: a chorus with 2 sopranos, 2 altos, 2 tenors and 2 bass voices grants him a large number of combinations of voices and thus constant change of timbre. The strings choir also has six parts, with both violins often conducted virtuosically. A chorus with 3 trumpets and 2 cornetti is even surpassed in tonal mass by the chorus composed of 2 clarini, 4 trumpets, and timpani. This large number of trumpets emphasizes the cheerful character of the work and is very luxurious by Austrian standards.

Gunar Letzbor and his ensemble Ars Antiqua Austria are proven specialists for Austrian baroque music. During recent years, they have rediscovered, performed and recorded polychoral Festive Masses by Weichlein, Ramhaufsky and Hochreither and thus Georg Muffat's magnificent 'Missa in labore requies' is a logical choice of repertoire. This work is the only surviving church music by Georg Muffat and is overwhelming in sonic impact and profundity but also a richness of melodic invention. In its polychoral design, the work is in the tradition of Salzburg Festive Masses, reflecting in their extraordinary musical opulence, the almost boundless material wealth of the prince bishops who commissioned them.