The Arian influence grew so strong during his tenure in the Imperial court that it wasn't until the end of the Constantinian dynasty and the appointment of Theodosius I that Arianism lost its influence in the Empire.

A local legend mentions that Theodosius I used the strong northern bora wind that is common in Ajdovščina and the Vipava Valley to his favor and disabled the enemy archers and pilum units with the help of the wind.

When Theodosius had left the western half of the empire to Valentinian II, he had put his own men in the highest civil offices, to keep a strong grasp on the whole empire.

Emperor Theodosius II convened the Second Council of Ephesus, and in remembrance of Cyril's role during the council of 431, the emperor, under strong influence of the eunuch Chrysaphius, a senior advisor and a close friend of Eutyches, asked Dioscorus, also a friend of Eutyches, to preside over the meetings.

Valens died in the Battle of Adrianople in 378 and was succeeded by Theodosius I, who adhered to the Nicene creed.

Two days after Theodosius arrived in Constantinople, 24 November 380, he expelled the Homoiousian bishop, Demophilus of Constantinople, and surrendered the churches of that city to Gregory Nazianzus, the leader of the rather small Nicene community there, an act which provoked rioting.

Although much of the church hierarchy in the East had opposed the Nicene creed in the decades leading up to Theodosius ' accession, he managed to achieve unity on the basis of the Nicene creed.

In the East, Emperor Theodosius I likewise professed the Nicene creed ; but there were many adherents of Arianism throughout his dominions, especially among the higher clergy.

When Theodosius ascended to the imperial throne in 380, he began on a campaign to bring the Eastern Church back to Nicene Christianity.

On his accession to the imperial throne, Theodosius offered to confirm Demophilus as bishop of the imperial city on the condition of accepting the Nicene Creed ; however, Demophilus refused to abandon his Arian beliefs, and was immediately ordered to give up his churches and leave Constantinople.

The accession of Theodosius I, a steadfast supporter of Nicene orthodoxy, was good news to those who wished to purge Constantinople of Arian and Apollinarian domination.

* First Council of Constantinople ( some authorities date this council to 383 ): Theodosius I calls a general council to affirm and extend the Nicene creed, and denounce Arianism and Apollinarism.

* Theodosius I abolishes the Greek Olympic Games, ending a thousand years of festivals, as part of the general Christian policy to establish universal Christian worship in accordance with the doctrines set forth in the Nicene Creed.

* First Council of Constantinople ( some authorities date this council to 381 ): Theodosius I calls a general council to affirm and extend the Nicene creed, and denounce Arianism and Apollinarism.

Despite his father's origins there is little to suggest that Stilicho considered himself anything other than a Roman, and his high rank within the Empire suggests that he was probably not Arian like many Germanic Christians but rather a Nicene Christian like his patron Theodosius I, who declared Nicene Christianity the official religion of the Empire.

Theodosius I briefly re-united the Empire: in 391 he officially adopted Nicene Christianity as the Imperial religion and ended official support for all other creeds and cults.

Theodosius offered to confirm him in his see, if he would subscribe the Nicene Creed.

However, Valen's successor Theodosius I effectively wiped out Arianism once and for all among the elites of the Eastern Empire through a combination of imperial decree, persecution, and the calling of the Second Ecumenical Council in 381, which condemned Arius anew while reaffirming and expanding the Nicene Creed.

Prior to this date, Constantius II ( 337-361 ) and Valens ( 364-378 ) had personally favored Arian or Semi-Arian forms of Christianity, but Valens ' successor Theodosius I supported the Trinitarian doctrine as expounded in the Nicene Creed from the 1st Council of Nicea.

According to early Christian sources, bishop Theophilus of Alexandria was Nicene patriarch when the decrees of emperor Theodosius I forbade public observances of any rites but Christian.

The temple survived until 390 AD, when the Christian emperor Theodosius I silenced the oracle by destroying the temple and most of the statues and works of art in the name of Christianity.

* 380 – Edict of Thessalonica: Emperor Theodosius I, with co-emperors Gratian and Valentinian II, declare their wish that all Roman citizens convert to trinitarian Christianity.

Theodosius I made Christianity the state religion of the empire in 391, and by the 5th century it was well established.

After adoption of Christianity as the only permissible Roman state religion under Theodosius I, Christian art began to change not only in quality and sophistication, but also in nature.

This was shortly after the Roman Emperor Theodosius I had issued a decree of death for Manichaeans in AD 382 and shortly before he declared Christianity to be the only legitimate religion for the Roman Empire in 391.

However, by the end of the 4th century, Emperor Theodosius I proclaimed Christianity as the state religion of the Roman Empire.

* 378 – 395: Theodosius I, Roman emperor, bans pagan worship, Christianity is made the official religion of the Empire.

* Emperor Theodosius I establishes Christianity as the official state religion.

Theodosius I is converted to Christianity.

* February 27 – Edict of Thessalonica: Theodosius I, with co-emperors Gratian and Valentinian II, declare their wish that all Roman citizens convert to trinitarian Christianity, in accordance with the patriarchs of Rome and Alexandria, implicitly rejecting the Arianism of the patriarch of Constantinople as heretical.

Aelia Eudocia Augusta ( c. 401 – 460 ) was the wife of Theodosius II, and a prominent historical figure in understanding the rise of Christianity during the beginning of the Byzantine Empire.

Athenais had been raised pagan, and had to convert to Christianity in order to marry Theodosius II.

* 380-Roman Emperor Theodosius I makes Christianity the official state religion

The emperor Julian made a short-lived attempt to revive traditional and Hellenistic religion and to affirm the special status of Judaism, but in 391 under Theodosius I Christianity became the official state religion of Rome, to the exclusion of all others.

The emperor Julian made a short-lived attempt to revive traditional and Hellenistic religion and to affirm the special status of Judaism, but in 391 under Theodosius I Christianity became the official state religion of Rome, to the exclusion of all others.

Apostasy, for example, is a violation of orthodoxy that takes the form of abandonment of the faith, a concept largely unknown before the adoption of Christianity as the state religion of Rome on February 27, 380 by Theodosius I ( see also First seven Ecumenical Councils and State church of the Roman Empire ).

The Olympic Games were eventually ended by Emperor Theodosius I ( r. 379 – 395 ) in 393, perhaps in a move to suppress paganism and promote Christianity, but chariot racing remained popular.

Under the influence of Pulcheria, Theodosius sent troops into battle against Persia, the fanaticism over the war by the people of the empire was described by Sozomen as " ready to do anything for the sake of Christianity.

* 380: Theodosius I declares Christianity the state religion of the empire.

On this date, Theodosius I decreed that only the followers of Trinitarian Christianity were entitled to be referred to as Catholic Christians, while all others were to be considered to be heretics, which was considered illegal.

Symmachus ' wealth enabled his patronage: he was involved in publication of the Commentarii in Somnium Scipionis by Macrobius Ambrosius Theodosius, and there is even a copy of the work corrected by his hand.