Final answer:
The first major center of polyphony was Notre Dame Cathedral in Paris, a pivotal location for the development of polyphonic music during the Renaissance period.
Step-by-step explanation:
The first major center of polyphony was Notre Dame Cathedral in Paris. Polyphony, which significantly developed during the Renaissance, involves multiple independent melodies being played or sung simultaneously. It marked a major change from the monophonic music of the Middle Ages and led to the use of larger ensembles and a blend of instruments across the vocal range.
Notre Dame was central to the development of polyphonic music, with composers like Léonin and Pérotin who worked there in the 12th and 13th centuries contributing significant compositions that are among the earliest examples of polyphony. These polyphonic structures still influence classical and sacred music today.