Music can be used as an oral historian.We have discovered traditions that use music to preserve history.What does that mean and what does this mean

Music can be used as an oral historian. We have discovered traditions that use music to preserve history. What does that mean and what does this mean to you? Talk about two different traditions (from two different continents) that are used in this way. Further, in what way do some popular forms of American music function within this scope? It is straightforward (literal) or is some cultural knowledge necessary? Explain this and be specific.