What is Su Wen and its historical significance?

Gregorian chant is also called "plainsong". Plainsong is characterized by a song sung in Latin. The melody of Plainsong is syllabic (that is, one note corresponds to one Latin syllable), gorgeous (one syllable is long), or aria (in between). It is a typical church music with eight modes (four positive modes and four variable modes, called church mode) and spectrum-by-spectrum notation (no fixed pitch, only melody direction). It not only occupies a large area, but also gets rid of the improvisation and oral teaching of folk music, making it a written and standardized classic culture, which has important historical significance in the cultural history.