Events By place Roman Empire March 1—Diocletian and Maximian appoint Constantius Chlorus and Galerius as Caesars. This is considered the beginning of the Tetrarchy.Constantius Chlorus marries Flavia Maximiana Theodora, stepdaughter of Maximian, after renouncing Helena, mother of Constantine I. Constantius Chlorus restores the northern Rhine border after defeating the Franks. Franks keep living in the north, because the Roman population has fled. Constantius Chlorus retakes northern Gaul f… (More on 293)