wikipediaConstantius I (Latin: Marcus Flavius Valerius Constantius Herculius Augustus;[2][3] 31 March c. 250 – 25 July 306), posthumously known after the sixth century as Constantius Chlorus (Greek: Κωνστάντιος Χλωρός, Kōnstantios Khlōrós, literally "Constantius the Green"),[4] was a Roman Emperor. He ruled as Caesar from 293 to 305[5] and as Augustus from 305 to 306. He was the junior colleague of the Augustus Maximian under the Tetrarchy and succeeded him as senior co-emperor of the western part of the empire.[6] Constantius ruled the West while Galerius was Augustus in the East. He was the father of Constantine the Great and founder of the Constantinian dynasty.
As Caesar, a junior emperor appointed by Diocletian, he defeated the usurper Allectus in Britain and campaigned extensively along the Rhine frontier, defeating the Alamanni and Franks. Upon becoming Augustus in May 305, Constantius launched a successful punitive campaign against the Picts beyond the Antonine Wall.[7] However, Constantius died suddenly at Eboracum (York) in July the following year.
Constantius's death and the acclamation of his son as Augustus by his army in 306 sparked civil wars ending in the collapse of the tetrarchic system of government inaugurated in 293 by Diocletian and the eventual resumption of dynastic rule over the whole empire by Constantine and his sons after the defeat of his co-emperor Licinius in 325.