Over the past few years, Józef ZEIDLER (1744-1806) has become established as a prominent name in Polish classicism. Many music manuscripts, including Zeidler’s, were once housed at the Cistercian monastery in Obra, and we can only speculate as to whether they arrived in Munich during World War II or at some earlier time, subsequent to the Prussian clampdown on monastic life in Poland. Notable among the Obra treasure trove found in Munich is Józef Zeidler’s Mass ex D which, to the extent of the labels knowledge, has not been preserved in any known Polish music collection. Dated to 1769, it is the earliest known Zeidler work. Zeidler’s Mass ex D leaves the old Baroque style behind in terms of its melodic lines, textures, and its approach to the liturgical text. The Mass ex D is monumental, technically dazzling, and bombastic, and is a fine display piece in which the young composer flaunts the rich and varied contents of his toolbox.