In the portraits of Costantine, we see evidence of new and traditional styles when depicting the face of the emperor.
On the one hand, Costantine is clean shaven, similar in style to the portraits of emperor Trajan but unlike portraits of 3rd century emperor Probus. He is portrayed with an imperial diadem in his hair, similar to that of an oriental King. Costantine is also portrayed with exceptionally large eyes, which perhaps symbolize divine inspiration or strenght of character.
On the other hand, the way Probus is depicted provides an example of how 3rd century military emperors were usually portrayed: bearded, with short military hair and crowned.