The Roman Empire lasted after Alaric for 1043 years untill the fall of Constantinople in 1453 to the Turks. It was not all decline in those years. There were periods of great strength in wich the empire was well respected and feared. In all that time, if they would have reverted back to a republic that the majority of people could believe in and would be willing to give their lives for, I am positive it would still exist today. Great empires like that of the Romans do not fall from without they fall from within when the people would rather be conqured than give their lives for their country!