Final answer:
Most medieval music was not instrumental; instead, it comprised both vocal and instrumental compositions, with vocal liturgical music like Gregorian chant being prevalent in the early medieval period.
Step-by-step explanation:
The statement that most medieval music was instrumental is false. Medieval music consisted of both sacred and secular forms, with liturgical music (primarily vocal and monophonic) being prevalent during the earlier part of the period, evolving into more complex polyphonic structures later on. Theory and notation advances during this time laid the foundations for future Western music practices. Although there was an emergence of purely instrumental music, especially for dance, it was not the predominant form. Surviving manuscripts show a mix of vocal and instrumental music, with a lot of vocal music - such as the famous Gregorian chants - being central to religious life.