Ancient Romans knew all about personality cults. Successful gladiators were the Beckhams and Ichiros of their day, celebrated in graffiti scrawled on city walls. Emperors from the time of Augustus (27 B.C.-A.D. 14) took it all one step further, with an official "cult" of the imperial personage that saw statues of rulers installed in dedicated temples known as sabasteia. The more ambitious among them (or perhaps the more unstable) sought to replace the empire's pre-existing religions, and in A.D. 41 all hell broke loose when the mad Emperor Caligula gave orders that a statue of himself be erected in the sacred precinct of the Jewish Temple in Jerusalem.

So visitors to the National Museum of Western Art finding themselves face to face with Julius Caesar or Augustus in the new show "Vixerunt Omnes: Romani ex Imaginibus" should be aware they're eyeballing not a person so much as a phenomenon. Though Rome's was the largest empire the world had then seen, with 5 million inhabitants within its borders circa A.D. 14, the individual mattered. Ridley Scott's 2000 blockbuster "Gladiator" may have been a load of Hollywood hokey, but it reflected one fundamental truth about imperial Rome: Personality was destiny.

As such, the portraiture on show is less about aesthetics than advertising, the flaunting of personal achievement. Even those of humble rank commissioned elaborate monuments, enjoying Andy Warhol's "five minutes of fame" until the next smart slab went up. (It's ironic that these most mundane of artworks have, by their survival, won a kind of immortality for their owners.)