"...The Chant proper to the Roman Church, the only chant she has inherited from the ancient fathers, which she has jealously guarded for centuries in her liturgical codices, which she directly proposes to the faithful as her own, which she prescribes exclusively for some parts of the liturgy, and which the most recent studies have so happily restored to their integrity and purity."

From Tra le Sollecitudini, Pope Pius X on Gregorian chant