Many theorists have argued that different types of music have emotional effects on people. Plato, for example, believed that because the Phrygian mode stirred up passions, it should be banned in the ideal city.
In oral traditional cultures, all cultural tradition and wisdom tended to be taught and circulated via musical performance. This type of transmission of knowledge by influential classes of musical performed is exemplified by the Homeric rhapsodes of classical antiquity, the African Griots, and the Balkan Guslari.
Many types of protest music convey political ideology, including the folk singers of the US in the 1960s and the rebetika of 19th and early twentieth century Greece.
Both Hitler and Stalin used song along with other forms of state sponsored creative works to inculcate political ideology, following Marx's theories.