Flavius Valerius Constantius
AD293 ~ AD306
Flavius Valerius Constantius was born in 250 and under the rule of Carus, was selected to govern Dalmatia. In 293 when the emperor Diocletian divided the roman empire in half he declared that under the new governing system each empire would be ruled by an Augustus with the support of a Caesar.
Constantius was declared Caesar of the western empire that was ruled by Maximian and later married Maximians' step daughter and together they had 6 children not including Constantine who was his first son to a prior marriage.
In 286 Carausius declared himself emperor in Britain and Gaul, and it was Constantius who was sent to defeat him in 293.
In 305 when both Maximian and Diocletianus retired, Constantius and Galerius became co-emperors with Severus and Maximinus as Caesars but when Constantius died in Britain during battle in 306, Constantine was elected emperor by the army.