CONSTANTIUS I (Gaius Flavius Valerius Constantius), called Constantius Chlorus.
- Gaius Flavius Valerius Constantius was born c. 350 A.D. at Illyricum. His nick-name "Chlorus" meant "the pale".
- He was a general and administrator under the Emperor Maximian.
- During this time he married a tavern-girl called Helena and they had a son, Constantine.
- In November 285 Diocletian had made Maximian co-Emperor.
- Diocletian now wanted to arrange a formal succession for the joint emperors, so on 1st March 293, Maximian adopted Constantius who was now his praetorian commander, as son and Caesar, while Diocletian adopted Galerius Valerius Maximianus as son and Caesar.
- In 286, Carausius, commander of the Roman North Sea fleet, had seized control of Britain and pronounced himself emperor. Maximian attempted to quell the revolt in 289, but had failed.
- Constantius was take over the task where Maximian had left off. He began in the summer of 293 by recapturing the territories in northern Gaul, including the major naval base at Gesoriacum (Boulogne).
- Later in the same year Carausius was murdered by Allectus, his treasurer, in a palace coup.
- Constantius waited for 3 years before launching an invasion (296). Constantius with part of his fleet cruised off the coast of Kent, while his praetorian commander, Asclepiodotus, sailed from the mouth of the Seine sneaking past the fleet of Allectus, off the Isle of Wight, in the fog, he landing near Clausentum (near Winchester). Allectus marched from London to meet him, and met him in battle near Silchester (North Hampshire). The forces of Allectus were beaten and he was killed.
- Meanwhile, Constantius, had sailed up the Thames where, according to a gold medallion found near Arras in 1922, he was welcomed by the Capital as REDDITOR LVCIS AETERNA, the Restorer of the Eternal Light.
- On 1st May 305 Diocletian and Maximian abdicated and Constantius and Galerius became the new senior emperors, while Maximinus Daia and Severus took their places as Caesars.
- Constantine was serving under Diocletian as a high ranking staff officer (and hostage to the chance of his ambition getting the better of him). He went to Boulogne where his father was preparing to leave for Britain to campaign against the Picts in the north.
- Constantine went with him and the campaign of 305 was a success.
- On 25th July 306 Constantius died at Eboracum (York). The army immediately proclaimed Constantine "Augustus" and senior emperor in the west in succession to his father.