Final answer:
Diocletian established the Tetrarchy, or rule of four, dividing the Roman Empire into more manageable parts to ensure effective governance and orderly succession.
Step-by-step explanation:
Diocletian and the Establishment of the Tetrarchy
Emperor Diocletian, who rose to power in 284 CE, realized that the vast size of the Roman Empire was impeding its effective governance. To address this issue, Diocletian established the Tetrarchy, which means the rule of four. The Tetrarchy involved four rulers, two senior emperors titled Augusti and two junior emperors titled Caesars.
Under this system, Diocletian ruled the eastern half, while his co-emperor Maximian ruled the west. About a decade later, each Augustus chose a Caesar to share responsibilities, creating a more manageable division of the empire.
Diocletian implemented the Tetrarchy to end a cycle of assassinations and bring an orderly succession of power. He also divided the empire into smaller provinces and larger units called dioceses, overseen by officials known as vicars, to simplify administration.
Another significant reform was the issuing of the Edict on Maximum Prices in 301, which aimed to curb inflation and stabilize the currency.
These reforms were intended to provide a more stable and secure environment for the Roman Empire, which was facing threats both internally and from external forces such as Persia and Germanic barbarians.
Although the Tetrarchy worked during Diocletian's reign, it quickly fell into disarray after his retirement, leading to civil wars and ultimately the rise of Constantine as the sole ruler of a reunited but transformed empire.