This coin from 295 AD is an argenteus, a denomination that Emperor Diocletian (284-305) had introduced the year before. With this issue Diocletian wanted to revive the traditional Roman silver coin, the denarius. The obverse shows a portrait of the emperor, while the reverse alludes to another reorganization that Diocletian had set up:
The design depicts the tetrarchs, the four rulers of the Roman Empire. Diocletian was the first emperor to recognize that his realm had become too big to be reigned by one man only. For this reason, he appointed his friend Maximian as co-emperor; from now on, the two were to share governmental power. On top of that, both emperors additionally selected a caesar as junior partner. Those four rulers are depicted on this coin while celebrating a mutual sacrifice.