In addition to his duties as a cleric, Proske devoted all his energies and spent his entire private income on the restoration of what he called "vere musica ecclesiae," the "true music of the Church."
This he considered to be the ancient Gregorian chant and especially the polyphonic works of the Renaissance masters (such as Palestrina, Nanini, Marenzio, Lassus, etc.).
Proske was a pioneer in the field, and the fact that his editions reflected only the German, Flemish, and Italian repertoires - excluding Spaniards for the most part, though he did include Victoria - does not diminish his amazing contributions to Sacred music.
Proske spent hours transcribing and arranging ancient polyphony, and rounded up the greatest singers in his city in order to have them sight-sing his newly copied manuscript to check for part-writing errors.
In 1853 Proske initiated the publication of his invaluable "Musica Divina", the fourth volume of which appeared in 1862 (finished by such prominent students as Franz Xaver Haberl).