=Arcadius=, eldest son of Theodosius the Great, succeeded his father A.D. 395. Under him the Roman power was divided into the eastern and western empire. He made the eastern empire his choice, and fixed his residence at Constantinople; while his brother Honorius was made emperor of the west, and lived in Rome. After this separation of the Roman empire, the two powers looked upon one another with indifference; and, soon after, their indifference was changed into jealousy, and contributed to hasten their mutual ruin. In the reign of Arcadius, Alaricus attacked the western empire, and plundered Rome. Arcadius married Eudoxia, a bold and ambitious woman, and died in the 31st year of his age, after a reign of 13 years, in which he bore the character of an effeminate prince, who suffered himself to be governed by favourites, and who abandoned his subjects to the tyranny of ministers, while he lost himself in the pleasures of a voluptuous court. =Arcānum=, a villa of Cicero’s near the Minturni. _Cicero_, bk. 7, _Letters to Atticus_, ltr. 10. =Arcas=, a son of Jupiter and Calisto. He nearly killed his mother, whom Juno had changed into a bear. He reigned in Pelasgia, which from him was called Arcadia, and taught his subjects agriculture and the art of spinning wool. After his death, Jupiter made him a constellation with his mother. As he was one day hunting, he met a wood nymph, who begged his assistance, because the tree over which she presided, and on whose preservation her life depended, was going to be carried away by the impetuous torrent of a river. Arcas changed the course of the waters, and preserved the tree, and married the nymph, by whom he had three sons, Azan, Aphidas, and Elatus, among whom he divided his kingdom. The descendants of Azan planted colonies in Phrygia. Aphidas received for his share Tegea, which on that account has been called the inheritance of Aphidas; and Elatus became master of mount Cyllene, and some time after passed into Phocis. _Pausanias_, bk. 8, ch. 4.――_Hyginus_, fables 155 & 176.――_Apollodorus_, bk. 3, ch. 8.――_Strabo_, bk. 8.――_Ovid_, _Fasti_, bk. 1, li. 470.――――One of Actæon’s dogs. =Arce=, a daughter of Thaumas, son of Pontus and Terra. _Ptolemy Hephæstion_. =Arcēna=, a town of Phœnicia, where Alexander Severus was born. =Arcens=, a Sicilian who permitted his son to accompany Æneas into Italy, where he was killed by Mezentius. _Virgil_, _Æneid_, bk. 9, li. 581, &c.