Final answer:
The question pertains to the transformation of the Roman Republic into the Roman Empire, marked by civil wars and the rise of Augustus Caesar as the undisputed ruler, and the eventual division and fall of the Western Empire.
Step-by-step explanation:
Roman Empire's Political Transformation
Just as competing emperors struggled for supremacy within a divided Roman Empire, the period between 60 BCE and 31 BCE was characterized by numerous military leaders who influenced Rome's transition from a Republic to an Empire. This era of decades of territorial expansion was marked by civil wars and political tumult, ultimately leading to the rise of a single ruler, Augustus Caesar, by 27 BCE. Under Augustus's rule, the Republic was maintained in name only, while the Roman Empire was truly established. Subsequent centuries saw the Empire face both internal strife, such as clashes with the Praetorian Guard and elite retreats to private estates, and external pressures, including aggressive Sassanids and organized barbarian populations. These factors, along with the complexities of managing an expansive empire, contributed to the emergence of the tetrarchy system by Emperor Diocletian, aiming to stabilize the empire.
The Empire eventually split into the Western Roman Empire and the Eastern Byzantine Empire, with the latter facing challenges both internally from powerful dynatoi elites and externally from conflicts with Persia and barbarian tribes. The continuous power struggles and shifting political structures culminated in the Western Empire's fall in the 5th century CE, while the Eastern Empire, now known as the Byzantine Empire, continued until its fall in 1453.