The definition of propaganda from Wikipedia is “information, especially of a biased or misleading nature, used to promote or publicize a particular political cause or point of view.”
When I think propaganda politics comes to mind. The Roman art used this in many ways, the fact that statues depicted leaders as powerful and worthy of the public’s trust is in itself propaganda. It appears that the rulers always wanted to “one up” the previous ruler in order to gain popularity with the public, pure propaganda. Augustus of Primaporta mixes up messages, a breastplate is used for battle but his depicts diplomacy. The cupid and dolphin are meant to let the masses know that he was of divine blood. This all lends to the appearance that he was a strong and fair ruler that was born to be a ruler.