Battleship Potemkin

Having watched this film has led me to look down a different avenue of sound.  While the film is silent i read up a little about the history and saw that it was considered one of the best propaganda films made.  This reminded me about what i read earlier (and for the life of me now, i can't remember where) that some people consider that a documentary can't be a documentary if narration is included as it means that what is said may be at the behest of whomever is paying for the making of it and as such is not neutral.  But here is a silent film about the uprising of a ships crew against the officers and it is considered one of the best propaganda films made.

I don't think there is a real correlation between the two and my ramblings but the thought that a silent film can be propaganda has got me thinking about how it could be used with sound.