The barbarians, which is a term that covers a varied and changing group of outsiders, were embraced by Rome, who used them as suppliers of tax revenue and bodies for the military, even promoting them to positions of power.
But Rome also lost territory and revenue to them, especially in northern Africa, which Rome lost to the Vandals at the time St. At the same time the Vandals took over the Roman territory in Africa, Rome lost Spain to the Sueves, Alans, and Visigoths.
By the time Rome became an empire, the territory covered by the term "Rome" looked completely different.
It reached its greatest extent in the second century C. Some of the arguments about the Fall of Rome focus on the geographic diversity and the territorial expanse that Roman emperors and their legions had to control.
This began in the early 4th century with Emperor Constantine, who was actively involved in Christian policy-making.
When Constantine established a state-level religious tolerance in the Roman Empire, he took on the title of Pontiff.There is no doubt that decay—the loss of Roman control over the military and populace—affected the ability of the Roman Empire to keep its borders intact.Early issues included the crises of the Republic in the first century BCE under the emperors Sulla and Marius, as well as that of the Gracchi brothers in the second century CE.Emperor Theodosius made Christianity the official religion in 390 CE.Since Roman civic and religious life were deeply connected—priestesses controlled the fortune of Rome, prophetic books told leaders what they needed to win wars, and emperors were deified—Christian religious beliefs and allegiances conflicted with the working of empire.Some historians maintain that the split into an eastern and western empire governed by separate emperors caused Rome to fall.Most classicists believe that a combination of factors including Christianity, decadence, the metal lead in the water supply, monetary trouble, and military problems caused the Fall of Rome.That influx of conquered peoples and lands changed the structure of the Roman government.Emperors moved the capital away from the city of Rome, too.Although he was not necessarily a Christian himself (he wasn't baptized until he was on his deathbed), he gave Christians privileges and oversaw major Christian religious disputes.He may not have understood how the pagan cults, including those of the emperors, were at odds with the new monotheistic religion, but they were, and in time the old Roman religions lost out.