What period or era have the same feature

Comma should appear after  the quote, 

True, because it rids of unwanted shadows or illusions.

Artists usually use musical imagery to make their compositions more unique and alive. imagery in music used to "show" music. because of that listeners feel what happens. they see music like complete composition. they hear sounds, they feel movement, they see a picture. it makes music deep. that's why  musical imagery is very important and is used by artists so frequently.