Short answers, pulled from the story.
Roman portraiture is known for its unusual realism and the desire to convey accurate likenesses of real individuals. Unlike ancient Greek portraits, which strived for idealization, Roman portrait sculpture is still considered one of the most realistic samples of the genre in the history of art. Some surviving busts even appear to show clinical signs in the faces depicted.
Some scholars believe Roman realism evolved from wax death masks taken from bodies and kept in home altars. Because the molds were made directly from the deceased, they provided accurate representations of typically Roman features. In the Republican era, these masks were also cast from living family members to preserve hyper-realistic likenesses.
By the imperial age, portrait sculpture was used to embed ideological messages in the pose, costume, and accoutrements of the figure. Since most emperors from Augustus onward were deified, some images were idealized. Augustus, for example as seen in the Blacas Cameo, was always portrayed as a man of around thirty-five even when images were made in his seventies.
The Severan Period marble portrait of Caracalla reflects a shift toward more geometric renderings of the human face to convey messages of power and authority. Nearly all representations of Caracalla show a frighteningly aggressive expression conveying military prowess. Subsequent emperors sought similar portraits, pushing Roman portraiture progressively further from individual likeness toward abstraction.
The Portrait of the Four Tetrarchs depicts the four rulers who divided rule of the Roman Empire among themselves. The figures are rendered in a near-identical geometric style that is not realistic but was chosen deliberately to signal the four rulers' ontological equality and the unity and strength of the empire. Presenting varied appearances might have led viewers to favor one ruler over the others.
Roman funerary art includes many portrait types, with married couple funerary reliefs among the most prominent. These reliefs were most often made for wealthy freedmen rather than the patrician elite. They reflect the broader Roman practice of using portraiture to establish societal legitimacy and commemorate individuals.