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 Χλωρός, Kōnstantios Khlōrós, lit. "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.