During his reign, the Roman Empire expanded to its highest extent
It is a fact that during his reign, the Roman Empire expanded to its highest extent. In late 194, Severus launched a brief punitive war across the eastern border, annexing the Kingdom of Osroene as a new province. Three years later, in the Battle of Lugdunum in Gaul, Severus defeated Albinus. Following the strengthening of his dominance over the western provinces, Severus conducted a brief, more successful war against the Parthian Empire in the east, sacking their capital Ctesiphon in 197 and stretching the eastern frontier to the Tigris. He then strengthened and expanded the Limes Arabicus in Arabia Petraea.
Severus initiated a campaign in the province of Africa in late 202. Quintus Anicius Faustus, the legatus legionis or commander of Legio III Augusta, had been fighting the Garamantes along the Limes Tripolitanus for five years. He conquered several settlements, including Cydamus, Gholaia, Garbia, and their capital Garama, which was located over 600 kilometers south of Leptis Magna. The empire also annexed the settlements of Vescera, Castellum Dimmidi, Gemellae, Thabudeos, and Thubunae in Numidia. By 203, Roman Africa's whole southern boundary had been considerably enlarged and re-fortified. Desert nomads could no longer plunder the region's interior and return to the Sahara in safety.
Severus went to Britain in 208 with the purpose of conquering Caledonia. Modern archaeological findings shed light on the breadth and scope of his northern campaign. Severus most likely arrived in Britain with an army of about 40,000 men, given the size of some of the camps he built during his campaign. He fortified Hadrian's Wall and reclaimed the Southern Uplands up to the Antonine Wall, which he also fortified. Severus established a 165-acre (67-hectare) camp south of the Antonine Wall at Trimontium, where he most likely gathered his men. Severus then thrust his troops north past the wall into the Caledonian territory, aided and supplied by a powerful naval force. Following in the footsteps of Agricola, Severus repaired and garrisoned many abandoned Roman forts along the east coast, including Carpow.
