The Lombard kingdom in Italy, weakened by the independent actions of many strong dukes, did not last long. In 774 it was conquered by the Franks, who had in the meantime established the most powerful and longest lasting of all the Germanic kingdoms that arose on the territory of the West Roman Empire. The shock and dismay felt by contemporaries throughout the Roman world on learning of Alaric s sack of the Eternal City in 410 were to echo down the centuries, leaving the impression that the fall of Rome was a major calamity, one of the greatest in history. Pagan writers attributed the sack of Rome to the abandonment of their ancient gods. In The City of God, St. Augustine argued against this charge and put forth the view that history unfolds according to God s design.
Modern historians advance a variety of theories to explain why Rome fell.
Some explanations have been rooted in psychological theory. Corrupt high-ranking bureaucrats and military leaders seeking private gain have also been cited as a key factor. Some historians blame nonhuman causes such as an exhaustion of the soil, drought, malaria, plague, or the presence of toxic amounts of lead in Roman dining pottery and water pipes. Such single-cause explanations usually reflect a personal bias or axe to grind. Most historians today attribute Rome s decline to a combination of interacting forces over a long period of time.