Final answer:
The Catholic Church had the most influence on medieval music through its promotion of Gregorian chant and the establishment of musical notation.
Step-by-step explanation:
The Catholic Church likely had the MOST influence on medieval music.
During the Middle Ages, the Catholic Church played a significant role in shaping musical practices and styles. It was responsible for the development and promotion of Gregorian chant, which was the predominant form of music in medieval times.
Additionally, the Church's influence extended to the establishment of musical notation and the cultivation of liturgical music.
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