The fate of Marcin Mielczewski's output shows the difficulties faced by researchers of early music. We know the titles of one hundred and twenty works by the composer, a quarter of which have not survived at all, and a quarter in fragments. The total of sixty works known are not original manuscripts, but two printed editions and handwritten copies, often differing from each other. The hymn of the Magnificat ending the Vesperae Dominicalesin the Kroměříž manuscript, it is written for a different set of instruments than in the copy from Gdańsk. Some of the scores were lost during World War II, and we know about their existence thanks to photographs. It is certain that the works of Mielczewski - the court musician of King Władysław IV Vasa and the bandmaster of his brother, Bishop Karol Ferdinand - inspired the creators of polyphonic church music, and were also adapted for the needs of the Lutheran liturgy. Bach could come into contact with the compositions of the Pole in the library at the school in Lüneburg where he attended. Mielczewski represents the times when Polish music was at the highest world level. After centuries, we are rediscovering the richness of our native Baroque culture, and the Wratislavia Cantans festival has played a significant role in restoring our musical memory since its first edition.