Borders of the Roman Empire
The borders of the Roman Empire, which fluctuated throughout the empire's history, were realised as a combination of military roads and linked forts, natural frontiers and man-made fortifications which separated the lands of the empire from the countries beyond.
The limes that protected the Empire from German raids.
Limes Africanus under Septimius Severus (The frontier of Roman Africa (dark tan) in the late 2nd century AD: Septimius Severus expanded the Limes Tripolitanus dramatically (medium tan), even briefly holding a military presence (light tan) in the Garamantian capital Garama in 203)
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.
Augustus of Prima Porta
Nerva (r. 96–98)
Trajan (r. 98–117)
Hadrian (r. 117–138)