Complex sentence: The origins of Polish music can be traced as far back as the 13th century, from manuscripts which have been found in Stary Sącz, containing polyphonic compositions related to the Parisian Notre Dame School.
Split into simpler sentences: The origins of Polish music can be traced as far back as the 13th century. Manuscripts from that period have been found in Stary Sącz, containing polyphonic compositions related to the Parisian Notre Dame School.