You are looking at a coin of Julian “the Apostate,” the last pagan emperor of Rome (r. 361-363). It’s easy to gloss over the features because so many appear similar to others of the ancient world, but indulge me a moment. The side profile of Julian shows him with a beard. The flip side of the coin has a large bull: both of these elements bucked trends of the day, which is all of a piece with the emperor’s reign.
Julian was raised as a child away from the court after many of his relatives were killed by the Christian ruler Constantius II in a grab for power. Perhaps this episode, alongside his education by a pagan tutor, caused him to turn against Christianity and attempt to bring back the old-timey pagan religion. The bull on the coin has many interpretations, but probably relates to something pagan — we know that he participated in a taurobolium involving bathing in the blood of a bull. It was supposed to bring luck or an extended lifespan or immortality. It brought Julian none of these things, since he was killed fighting in battle against the Persians two years into his rule.
The beard thing is interesting, because Roman emperors just weren’t doing that in the fourth century. Like any hair style that strays far from the customary norm, the decision to go bearded was a conscious one. For Julian, it meant perhaps modeling himself after earlier emperors like the famed Stoic philosopher-ruler Marcus Aurelius, who had died a century and a half before Julian’s reign.
The thing is, Julian couldn’t stem the tide of history — obviously, since Paganism died and Christianity resumed after his death (and that’s why we call him “the Apostate” instead of “the alternative thinker”). He praised his beard in a long humble-brag satirical work called “Misopogon,” or “The beard-hater”, but he does so anachronistically. He thought the lice in his beard made him more manly, as did his other extreme habits, like curtailing his food and trying to endure extreme cold. The lice, the diet, the cold . . . All habits popular with the Christian ascetics of his own day. He might be astonished to realize he had more in common with contemporary Christians than his Stoic heroes.
Source(s): _Misopogon_- translated for the Loeb Classical Library by Wilmer Cave Wright, 1913.. Online version @attalus.org.