They don't teach you this in school…
Lucius Septimius Severus (/səˈvɪərəs/;[5] Latin: [ˈɫuːkiʊs sɛpˈtɪmiʊs sɛˈweːrʊs]; 11 April 145 – 4 February 211) was Roman emperorfrom 193 to 211. He was born in Leptis Magna, Libya in the Roman province of Africa.[6] As a young man he advanced through the customary succession of offices under the reigns of Marcus Aurelius and Commodus. Severus was the final contender to seize power after the death of the emperor Pertinax in 193 during the Year of the Five Emperors.
In 208 Severus travelled to Britain with the intention of conquering Caledonia. Modern archaeological discoveries illuminate the scope and direction of his northern campaign.[78]Severus probably arrived in Britain with an army of over 40,000, considering some of the camps constructed during his campaign could house this number.[79]
He strengthened Hadrian's Wall and reconquered the Southern Uplands up to the Antonine Wall, which was also enhanced. Supported and supplied by a strong naval force,[80] Severus then thrust north with his army across the wall into Caledonian territory. Retracing the steps of Agricola of over a century before, Severus rebuilt and garrisoned many abandoned Roman forts along the east coast, such as Carpow.[81]