Centuries

2-3

Christian Hymns

4-7 

Decline in community participation memorization in music

8-11

Music learnt from page vernacular (non-liturgical songs) imposition of Roman rite polyphony

12-15

Focus on ordinary mass 

16-19

Luther (Music: People) Trent vanished "all vocal/ instrumental music". 

18

Return to Gregorian Music to serve text.