surnamed CHLORUS (o( Χλωρός), "the Pale," Roman emperor, A. D. 305-306, the father of Constantine the Great, was the son of one Eutropius, of a noble Dardanian family, and Claudia, the daughter of Crispus, who was the (younger ?) brother of the emperors Claudius II. and Quintilius. He was probably born in 250. Distinguished by ability, valour, and virtue, Constantius became governor of Dalmatia during the reign of the ermperor Carus, who, disgusted with the extravagant conduct of his son Carinus, intended to adopt and appoint as his successor the more worthy Constantius. Death prevented Carus from carrying that plan into execution, and the reward of Constantius was left to the emperors Diocletian and Maximian, who had experienced that the government of the immense Roman empire, in its perpetual and hostile contact with so many barbarians, was a burden too heavy not only for one, but even for two emperors, however distinguished they were. They consequently resolved that each should appoint a co-regent Caesar, and their choice fell upon Constantius, who was adopted by Maximian, and Galerius, who was adopted by Diocletian. Both the Caesars were obliged to repudiate their wives, and Galerius was married to Valeria, the daughter of Diocletian, while Constantius received the hand of Theodora, the daughter of the wife of Maximian. Their appointment as Caesars took place at Nicomedeia on the 1st of March, 292. The government of the empire was distributed among the four princes in the following manner: Constantius was set over the provinces beyond the Alps, that is, Gaul, Britain, and Spain (?); Galerius received both the Illyriae and Moesia, an extensive tract comprising all the countries from the Inn in Germany to mount Athos and the shores of the Archipelago, and from the Adriatic Sea to the mouth of the Danube; Maximian governed Italy and Africa; and Thrace, Egypt, and all the Asiatic provinces were reserved for the authority of Diocletian. The first and most important business of Constantius was the reunion of Britain with the empire, as Carausius had succeeded in making himself independent of the authority of Diocletian and Maximian. [CARAUSIUS.] After the murder of Carausius by Allectus in 293, this officer seized the government; but Britain was taken from him after a struggle of three years [ALLECTUS], and Constantius established his authority there. Some time afterwards, the Alemanni invaded Gaul. A pitched battle took place, in 298, between them and Constantius at Lingones, in Lugdunensis Prima, now Langres: the Romans were nearly routed, when Constantius restored the battle, defeated the enemy, and killed either 60,000 or 6000 barbarians. They suffered another defeat at Vindonissa, now Windish, in Switzerland : there are doubts with regard to this battle. After the abdication of Diocletian and Maximiian, in 305, Constantius and Galerius assumed the title and dignity of Augusti, and ruled as co-emperors. Constantius died fifteen months afterwards (25th of July, 306) at Eboracum, now York, on an expedition against the Picts, in which he was accompanied by his son Constantine, whom he had by his first wife, Helena, whom he had repudiated. The same Constantine, afterwards the Great, succeeded him in his share of the government. Constantius was one of the most excellent characters among the later Romans, and it is to be regretted that we know so little about him. His administration of his provinces procured him, great honour, for he took the most lively interest in the welfare of the people, and was so far from imitating the rapacity of other governors, that he was not even provided with such things as are necessary to men of his rank, though a vulgar appellation calls them luxuries. In his abstinence from luxuries he seems, however, to have shewn some affectation. The Pagans praised him for his humanity, and the Christians for his impartiality and toleration. Theophanes calls him Χριστιανόφρων, or a man of Christian principles. His conduct during the persecution of the Christians by Diocletian was very humane. It is not known whence he received the surname of Chlorus, or the Pale, which is given to him only by later Byzantine writers. Gibbon (vol. ii. p. 118, note 1. ed. 1815) observes, that any remarkable degree of paleness seems inconsistent with the rubor mentioned in the Panegyrics (5.19). Besides his son and successor, Constantine, Constantius had by his second wife, Theodora, three sons and three daughters, who are mentioned in the genealogical table prefixed to the life of CONSTANTINUS I. (Eutrop. 9.14_23; Aurel. Vict. Caes. 39, &c., Epit. 39; Zosim. 2.7, &c.; Theophan. pp. 4-8, ed. Paris; Panegyric. Veter. 4.3, 6.4, 6; Euseb. Vit. Cost. 1.13-21; Treb. Pollio, Claudius, 3. 13; Ael. Spart. Ael. Verus, 2; Vopiscus, Carinus, 16, 17, Aurelianus, 44, Probus, 22; Amm. Marc. 19.2.)