From its origin as a city-state on the peninsula of Italy in the 8th century BC, to its rise as an empire covering much of Southern Europe, Western Europe, Near East and North Africa to its fall in the 5th century AD, the political history of Ancient Rome was closely entwined with its military history. The core of the campaign history of the Roman military is an aggregate of different accounts of the Roman military's land battles, from its initial defense against and subsequent conquest of the city's hilltop neighbors on the Italian peninsula, to the ultimate struggle of the Western Roman Empire for its existence against invading Huns, Vandals and Germanic tribes. These accounts were written by various authors throughout and after the history of the Empire. Following the First Punic War, naval battles were less significant than land battles to the military history of Rome due to its encompassment of lands of the periphery and its unchallenged dominance of the Mediterranean Sea.

The Roman Empire was the post-Republican state of ancient Rome. It is generally understood to mean the period and territory ruled by the Romans following Octavian's assumption of sole rule under the Principate in 27 BC. It included territories in Europe, North Africa, and Western Asia and was ruled by emperors. The fall of the Western Roman Empire in 476 AD conventionally marks the end of classical antiquity and the beginning of the Middle Ages.