Constantius I (Latin: Marcus Flavius Valerius Constantius Herculius Augustus; 31 March c. 250 – 25 July 306) was Roman Emperor from 293 to 306, commonly known as Constantius Chlorus (Greek: Κωνστάντιος , Kōnstantios Khlōrós, literally "Constantius the Pale"). He was the father of Constantine the Great and founder of the Constantinian dynasty.

As Caesar, he defeated the usurper Allectus in Britain and campaigned extensively along the Rhine frontier, defeating the Alamanni and Franks. Upon becoming Augustus in 305, Constantius launched a successful punitive campaign against the Picts beyond the Antonine Wall. However, Constantius died suddenly in Eboracum (York) the following year. His death sparked the collapse of the tetrarchic system of government inaugurated by the Emperor Diocletian.

Born in Dardania, Constantius was the son of Eutropius, whom the Historia Augusta claimed to be a nobleman from northern Dardania, in the province of Moesia Superior, and Claudia, a niece of the emperors Claudius II and Quintillus Modern historians suspect this maternal connection to be a genealogical fabrication created by his son Constantine I, and that his family were of humble origins.

...
Wikipedia