The "Bayrischen Adls Beschreibung" ("Description of the Bavarian nobility") compiled by Johann Michael Wilhelm von Prey zu Strasskirchen (1690-1747) is the most extensive collection of genealogical data of Old Bavarian noble families.
Comprising 33 folio-sized volumes, the rather voluminous work, which was "vermehret, mit Wappen gezieret und in die gegenwerhtige ordnung gebracht" ("complemented, adorned with coats of arms and arranged in the current order") by the Chamberlain of Freising with the aid of earlier works by the Prince-Bishop of Freising Johann Franz Eckher von Kapfing (1649-1727) lists and describes more than 2.500 family names.
The work remained a fragment, however: Important families such as the Maxlrain, Nothafft, Ortenburg or Seyboltstorff families, but also less important, but rather well-known families such as the Münchauer, Reitorner, Tunz or Zachreis families are not mentioned at all or only in a few sentences, together with their coat of arms. In contrast, Prey's collection contains some families which one would not expect to find there, given their importance or nationality.
Prey's descriptions of the nobility are - based on the possibilities and historical methods of their time - a compilation of his own and other persons' genealogical works and of excerpts from deeds, chronicles and compendia of coats of arms, for which reason the articles on the individual families differ rather strongly in depth, exactness and type of representation. The clean copy was produced in the years 1740/ 41. Today, the work is preserved by the Bayerische Staatsbibliothek (Bavarian State Library), bearing the shelf mark Cgm 2290.
A history of origins, including an overview of the family names represented in the "Adls Beschreibung" was written by Niklas Frhr. von Schrenck und Notzing (Register zur bayerischen Adelsgenealogie (Genealogia Boica 4), Munich 1974).