Well, the Roman Empire had many problems. It slowly broke down, it didn't happen in one day.
I wonder what led to the fall of the Roman Empire?
Christianity took hold of ancient times. Romans were becoming more loyal to Christianity than to Rome.
Roman Emperors were often assassinated because Roman citizens were not happy with the Emperors
The Roman Empire had grown so large, that it couldn't protect itself, or provide its citizens neither food nor luxury.
The Roman empire had grown so large that it couldn't protect itself. Neighboring civilizations attacked from different sides of the Roman Empire. Rome didn't have enough armies to protect itself.
Military and Rome's citizens
Not enough young men in Rome contributed to the army. Rome's citizens didn't think Rome was worth saving. Rome's armies couldn't win wars and battles.Parts of the Roman Empire were conquered and Rome shrank down.