Monastic schools, long considered the principal centers of learning, were first replaced by cathedral schools, and later, universities. But from the monastic schools to the universities with their more divergent curriculum, most literate people still had ties to the Church. Roger Bacon, for example, in addition to being the chief forunner of the scientific method of observation and experiment was a Franciscan monk, and Thomas á Becket was an archdeacon prior to his appointment as Chancellor of England. So many references of society, music, literature, etc., came from the pen of the clergy. This explains why Medieval Latin treatises such as the Musica enchiriadis, dating from the 9th century (or earlier), ignore secular music, because their primary interest was music of the Church. Reference to secular music including instrumental music would not appear until after 1150, requiring contemporary scholars to speculate as to the type of music to which the common folk danced and sang.2