C. James Madison
(I needed there to be 20 characters to answer so ¯\_(ツ)_/¯ )
the impact on the Roman empire had on the world was people known for their military politics and social intuitions the ancient Romans Conquer vast amounts of land in Europe north Africa built roads and spread Latin their language far and wide.
population shifts the population of Western Europe became more rural as Roman centres of trade collapsed, Nobles retreated to rural areas and the cities were left without strong leadership other City dwellers move to rural areas to grow their own food.
you might be wondering what were the causes and effects of the fall of Rome external military...it's effect spread across the Empire... After Rome was divided a powerful group of hands began moving West than numbers growing with captured prisoners a new allies people from all walks of life for eager to repeat the rewards of War.
if Rome had not fallen we would never have dark ages - 30000 days lost of days of ages he went would have landed on the moon and invented the internet in the 11th century so that we today had populated at least dozens of planets in our galaxy.