The Cyprian Plague decimated the workforce and the army.
The collapse was halted by , a pragmatic reformer who realized the empire was too large for one man to rule. He established the Tetrarchy (Rule of Four), dividing the empire into Eastern and Western halves, each governed by an "Augustus" and a junior "Caesar." The Roman Empire from Severus to Constantine
Recognizing that the empire’s wealth and threats were now in the East, he moved the capital to Byzantium, renaming it "New Rome" (Constantinople). Conclusion The Cyprian Plague decimated the workforce and the army
The empire physically broke apart into three pieces: the Gallic Empire in the west, the Palmyrene Empire in the east, and the Roman core. Diocletian and the Tetrarchy (284–305 AD) Conclusion The empire physically broke apart into three
The silver content of Roman coins dropped to nearly zero.
Germanic tribes crossed the Rhine and Danube, while the Sassanid Persians pressured the East.
By the time of Constantine’s death in 337 AD, the Roman Empire was unrecognizable from the one Severus had inherited. The Mediterranean world had shifted from a pagan, Rome-centered principate to a Christian, East-leaning autocracy. This "Late Antiquity" set the stage for the Byzantine Empire in the East and the eventual rise of medieval Europe in the West.