Why is hellenistic civilization an example of cultural diffusion?

Cultural diffusion occurs when one dominant culture is able to spred its influence to further territories. Hellenic culture was a mix of Hellenic, Greek, Persian, Indian etc. but it jad its distinctive features like democracy, education, the phenomenon of Polis which is a city that is a country at the same time. Since Greece controlled the sea and had a strong military, it was able to diffuse its culture onto the conquered regions.