At the height of its power, the Roman Empire held more than two million square miles of territory containing over a hundred million people. Throughout the centuries of its existence, the Empire brought major advancements in engineering, architecture, science, art, and literature. By the beginning of the 5th Century, decades of political corruption, economic crisis, and an overburdened military had exacted a severe toll on the stability of the Empire. This paved the way for severe incursions from aggressive barbarian tribes, leading to a decline from which Rome would not recover. Now citizens, soldiers, and allies of Rome must unite to protect the Empire.