Following the defeat of Mark Anthony and Cleopatra, Octavian received the title of "Augustus" from the Senate in 27 BCE, becoming the first Roman Emperor. If veristic (verism) portraits were governed by conventions, how do we make sense of the stylistic changes introduced by Augustus Ceasar when he became Emperor?

Following the defeat of Mark Anthony and Cleopatra, Octavian received the title of "Augustus" from the Senate in 27 BCE, becoming the first Roman Emperor. If veristic (verism) portraits were governed by conventions, how do we make sense of the stylistic changes introduced by Augustus Ceasar when he became Emperor?