This person fought under Carus in Persia and was appointed as a co-ruler after the death of Numerian.  
This person fought under Carus in Persia and was appointed as a co-ruler after the death of Numerian.  He gained full control when Carinus was killed by his own men and among his accomplishments were gaining Britain and checking the Persians. He tried to restore the gold standard, but his attempts to regulate prices proved ruinous, which helped result in his most famous decision. FTP, name this Roman emperor who formally divided the Roman empire in half.
This person fought under Carus in Persia and was appointed as a co-ruler after the death of Numerian.  
Gaius Aurelius Valerius Diocletianus