From the folder accompanying an Olympia CD OCD 321 Musica Antiqua Polonica:

"Zielenski was a composer, organist and Kapelmeister at the court of the Polish primate Wojciech Baranowski. Little is known about the life and work of Mikolaj Zielenski, who lived at the turn of the 17th century. Indeed too little considering the volume of his work and its historical significance. The music created thanks to his exceptional gift allowed Zielenski to take place in the history of music whereby he is even regarded as the best Polish composer before Chopin.

Szymon Skrowolski, a historian contemporary to Zielenski, classified him as a member of a group of Polish composers who had been educated in Rome: "in media Roma exercitati". ... It is quite certain that Zielenski studied the work of Palestrina, whose compositions were recognized by the Council of Trent as the stylistic paragon and pattern of church polyphony. He also became familiar with the compositions of the Gabrieli’s (Andrea and his nephew Giovanni)... The mastery of polychoral style ...brought to Zielenski the reputation of ‘the most perfect Venetian’ in Poland."