THEODOSIUS I, ROMAN EMPEROR. — Born at Cauca on 11 January 347, died at Milan on 17 January 395. After entering the army, he followed his father on campaigns in Britain and Africa, but after the latter’s tragic death (376) he retired into private life. He was recalled to service by Gratian after the battle of Adrianople (378) with the rank of magister equitum; shortly afterwards he was named Augustus (January 379) and entrusted with the governance of the Eastern Empire. He immediately set about pacifying the provinces that were being ravaged by bandits through a combination of prudent military and diplomatic action.
THEODOSIUS I, ROMAN EMPEROR — Medallion of Theodosius I with Valentinian II and Arcadius. Silver shield from 388 with the inscription: DN THEODOSIVS PERPET. AUG. OB DIEM FELICISSIMVM X. — Madrid, Royal Academy.
Ambrose vigorously protested the brutal act and wrote a letter to the Emperor threatening him with excommunication unless he did penance; after some hesitation, Theodosius humbly submitted to the bishop’s injunctions and was readmitted to Communion at Christmas 390 (St Ambrose, Epist., 51: De obitu Theodosii: PL 16, 1209-14, 1447-68).
Having returned to the East, Theodosius still had to fight against the barbarians, with whom, after defeating them, he concluded a peace treaty in 392. In the West, however, another usurper was stirring: the general Arbogast, after the death of Valentinian II (May 392)—possibly by his own hand—had the rhetorician Flavius Eugenius proclaimed emperor. Relying on the pagan party led by the Praetorian Prefect Nicomachus Flavianus, Eugenius advanced into Italy; Theodosius marched against him and defeated him near the Frigidus River (Friuli). Eugenius and Arbogast were slain in battle (summer 394). The Roman Empire once again fell into the hands of a single sovereign capable of ensuring welfare and tranquillity for all, but hopes were soon dashed, for Theodosius fell gravely ill and died at Milan in January 395, leaving as heirs his two sons Arcadius and Honorius, whom he had already named Augusti in 393.
While Theodosius’ activity was beneficial for the Empire, no less significant was his religious policy regarding Catholicism and paganism; he indeed sanctioned the definitive triumph of the former over the various heretical movements and brought about the disappearance of the latter, which still had fanatical supporters among the senatorial class. Theodosius did not persecute individuals directly, but by continuing the policy of Constantius II and Gratian he fully achieved his goal. In 381 and 383 he deprived apostates of civil rights (Cod. Theod., XVI, 7, 1-2). After Gratian’s death, he sent the Prefect Cynegius to Egypt with explicit orders to ban idolatry and close the temples. While in Rome after his victory over Maximus, he rejected the repeated petitions of the Senate that sought to restore the altar of Victory; indeed, in a speech he urged the senators themselves to abandon their pagan superstitions and embrace Catholicism. Shortly afterwards he withdrew all state subsidies for temple cults and banned every public pagan ceremony in Rome, threatening severe penalties for officials who tolerated them (ibid., XVI, 10, 10); the same decree was extended to Egypt (ibid., XVI, 10, 11) and in 392 to the entire Empire, imposing fines and confiscations on transgressors (ibid., XVI, 10, 12). Finally, after his victory over the usurper Eugenius, he enforced all previously enacted laws against paganism with greater rigor.
This campaign against idolatry, inspired not only by Theodosius’ conviction as a Christian but also by his recognition that paganism could no longer sustain the old Empire—beset on all sides by barbarians—only Catholicism could infuse it with a new vitality and, by remaining true to its Catholic identity, preserve its permanence. The true and only Christianity of Theodosius, therefore, could only be the Catholic faith, the same one preserved in Rome by Peter and taught by his successor Damasus (ibid., XVI, 1, 2). From this sprang all his religious policy: combating heresies, and in particular that which in the 4th century had most gravely assailed Catholic orthodoxy—Arianism. From the very beginning of his reign, having fallen ill in Thessalonica, he sought baptism from the local bishop, but only after ascertaining that he was orthodox. Once settled in Constantinople in 380, his first concern was to induce the Arian patriarch Demophilus to adhere to the Catholic faith; when Demophilus refused, Theodosius recognized the Catholic St Gregory, to whom he restored all the churches of the city (ibid., XVI, 5, 6). He took part in the Council of 381 and confirmed its decisions against heretics (ibid., XVI, 1, 3). In 383 he attempted a reconciliation among the various factions, summoning their leaders to Constantinople to examine their respective professions of faith; the discussions came to nothing, and so Theodosius, accepting the Catholic position, had all other creeds burned and issued several edicts forbidding heretical assemblies (ibid., XVI, 5, 11-13).
Thus, through his multifaceted legislative activity, Arianism was soon eradicated entirely from the Empire.