Rome's Imperial Crisis has been difficult for historians to summarize, which is why, despite being one of the most intriguing periods in Roman history, it is often overlooked by people who have chosen to focus on the more cohesive periods before and after it. Even though he is best remembered for his religious reforms and what his (mostly Christian) admirers described as his spiritual enlightenment, Constantine was also an able and effective ruler in his own right. Rising to power in a period of decline and confusion for the Roman Empire, he gave it a new and unexpected lease on life by repelling the repeated invasions of the Germanic tribes on the Northern and Eastern borders of the Roman domains, even going so far as to re-expand the frontier into parts of Trajan's old conquest of Dacia (modern Romania), which had been abandoned as strategically untenable.

However, it can be argued that despite his military successes – the most notable of which occurred fighting for supremacy against other Romans – Constantine may well have set the stage for the ultimate collapse of the Roman Empire as it had existed up until that point. It was Constantine who first decided that Rome, exposed and vulnerable near the gathering masses of barbarians moving into Germania and Gaul, was a strategically unsafe base for the empire, and thus he expanded the city of New Rome on the Dardanelles Straits, creating what eventually became Constantinople. By moving the political, administrative, and military capital of the empire from Rome to the East, as well as the imperial court with all its attendant followers, Constantine laid the groundwork for the eventual schism which saw the two parts of the Roman Empire become two entirely separate entities, go their own way, and eventually collapse piecemeal under repeated waves of invasion.