(Θεοδόσιος). (1) Surnamed The Great, Roman emperor of the East, A.D. 378-395. He was the son of the general Theodosius who restored Britain to the Empire, and was beheaded at Carthage in the reign of Valens (A.D. 376). The future emperor was born in Spain about A.D. 346. He received a good education; and he learned the art of war under his own father, whom he accompanied in his British campaigns. During his father's lifetime he was raised to the rank of Duke (dux) of Moesia, where he defeated the Sarmatians (374) and saved the province. On the death of his father he retired before court intrigues to his native country. He acquired a considerable military reputation in the lifetime of his father; and after the death of Valens, who fell in battle against the Goths, he was proclaimed emperor of the East by Gratian, who felt himself unable to sustain the burden of the Empire. The Roman Empire in the East was then in a critical position; for the Romans were disheartened by the bloody defeat which they had sustained, and the Goths were insolent in their victory. Theodosius, however, showed himself equal to the difficult position in which he was placed; he gained two signal victories over the Goths, and concluded a peace with the barbarians in 382.
In the following year (383) Maximus assumed the imperial purple in Britain, and invaded Gaul with a powerful army. In the war which followed Gratian was slain; and Theodosius, who did not consider it prudent to enter into a contest with Maximus, acknowledged the latter emperor of the countries of Spain, Gaul, and Britain, but he secured to Valentinian, the brother of Gratian, Italy, Africa, and western Illyricum. But when Maximus expelled Valentinian from Italy in 387, Theodosius espoused the cause of the latter, and marched into the West at the head of a powerful army. After defeating Maximus in Pannonia, Theodosius pursued him across the Alps to Aquileia. Here Maximus was surrendered by his own soldiers to Theodosius and was put to death. Theodosius spent the winter at Milan, and in the following year (389) he entered Rome in triumph, accompanied [p. 1566] by Valentinian and his own son Honorius. Two events in the life of Theodosius about this time may be mentioned as evidence of his uncertain character and his savage temper. In 387 a riot took place at Antioch, in which the statues of the emperor, of his father, and of his wife were thrown down; but these idle demonstrations were quickly suppressed by an armed force. When Theodosius heard of these riots, he degraded Antioch from the rank of a city, stripped it of its possessions and privileges, and reduced it to the condition of a village dependent on Laodicea. But in consequence of the intercession of Antioch and the Senate of Constantinople, he pardoned the city, and all who had taken part in the riot. The other event is an eternal brand of infamy on the name of Theodosius. In 390, while the emperor was at Milan, a serious riot broke out at Thessalonica, in which the imperial officer and several of his troops were murdered. Theodosius resolved to take the most signal vengeance upon the whole city. An army of barbarians was sent to Thessalonica; the people were invited to the games of the Circus; and as soon as the place was full, the soldiers received the signal for massacre. For three hours the spectators were indiscriminately exposed to the fury of the soldiers, and 7000 of them, or, as some accounts say, more than twice that number, paid the penalty of the insurrection. St. Ambrose, Archbishop of Milan, represented to Theodosius his crime in a letter, and told him that penitence alone could efface his guilt. Accordingly, when the emperor proceeded to perform his devotions in the usual manner in the great church of Milan, the archbishop stopped him at the door, and demanded an acknowledgment of his guilt. The conscience-struck Theodosius humbled himself before the church, which has recorded his penance as one of its greatest victories. He laid aside the insignia of imperial power; in the posture of a suppliant in the church of Milan he asked pardon for his great sin before all the congregation; and, after eight months, the emperor was restored to communion with the Church.
Theodosius spent three years in Italy, during which he established Valentinian II. on the throne of the West. He returned to Constantinople towards the latter end of 391. Valentinian was slain in 392 by Arbogastes, who raised Eugenius to the Empire of the West. This involved Theodosius in a new war; but it ended in the defeat and death both of Eugenius and Arbogastes in 394. Theodosius died at Milan, four months after the defeat of Eugenius, on the 17th of January, 395. His two sons, Arcadius and Honorius, had already been elevated to the rank of Augusti, and it was arranged that the Empire should be divided between them, Arcadius having the East, and Honorius the West. Theodosius was a firm Catholic, and a fierce opponent and persecutor of the Arians and all heretics. It was in his reign also that the formal destruction of paganism took place; and we still possess a large number of the laws of Theodosius, prohibiting the exercise of the pagan religion, and forbidding the heathen worship under severe penalties, in some cases extending to death.
(2) A Roman emperor of the East, A.D. 408-450. He was born in 401, and was only seven years of age at the death of his father Arcadius, whom he succeeded. Theodosius was a weak ruler; and his sister Pulcheria, who became his guardian in 414, possessed the virtual government of the Empire during the remainder of his long reign. The principal external events in the reign of Theodosius were the war with the Persians, which only lasted a short time (421-422), and was terminated by a peace for a hundred years; and the war with the Huns, who repeatedly defeated the armies of the emperor, and compelled him at length to conclude a disgraceful peace with them in 447 or 448. Theodosius died in 450, and was succeeded by his sister Pulcheria, who prudently took for her colleague in the Empire the senator Marcian, and made him her husband. Theodosius had been married in 421 to the accomplished Athenas, the daughter of the sophist Leontius, who received at her baptism the name of Eudocia. Their daughter Eudoxia was married to Valentinian III., the emperor of the West. In the reign of Theodosius, and that of Valentinian III., was made the compilation called the Codex Theodosianus. It was published in A.D. 438. It consists of sixteen books, which are divided into titles, with appropriate rubricae or headings; and the constitutions belonging to each title are arranged under it in chronological order. The first five books comprise the greater part of the constitution which relates to ius privatum; the sixth, seventh, and eighth books contain the law that relates to the constitution and administration; the ninth book treats of criminal law; the tenth and eleventh treat of the public revenue and some matters relating to procedure; the twelfth, thirteenth, fourteenth, and fifteenth books treat of the constitution and the administration of towns and other corporations; and the sixteenth contains the law relating to ecclesiastical matters.
Literary.(1) Of Bithynia, a mathematician, mentioned by Strabo and by Vitruvius, the latter of whom speaks of him as the inventor of a universal sun-dial.
(2) Of Tripolis, a mathematician and astronomer of some distinction, who appears to have flourished later than the reign of Trajan. He wrote several works, of which the three following are extant, and have been published: (a) Σφαιρικά, a treatise on the properties of the sphere, and of the circles described on its surface; (b) Περὶ Ἡμερῶν καὶ Νυκτῶν; and (c) Περὶ Οἰκήσεων.