After the Fall of Rome, Arianism dominated.

ABSTRACT: In 380, Emperor Theodosius made the Trinitarian version of Christianity the state religion of the Roman Empire. This was the birth of the Roman Church. In the fifth century, Arian Germanic immigrants dominated the Western Empire and the West was Arian once again. But they tolerated the Roman Church and it actually grew in strength.

This is an article in the series that explains how the Trinity doctrine became established in the Church. The current article considers the events of the Fifth Century.


The Origin of the Roman Church

In the year 379, Theodosius became emperor. One year later, in 380, he issued an edict that made the Trinity doctrine the sole state religion of the Roman Empire. In this way, the Trinity doctrine became the identifying mark of the Roman Church, understood as the Church of the Roman Empire.

While the Nicene Creed still identifies the “one God” as the Father, Theodosius’ edict identified the “one God” as the Father, Son, and Holy Spirit. It was, therefore, a significant ‘advance’ on the Nicene Creed. As discussed, when the Arian Controversy began, the ‘orthodoxy’ was that the Son is distinct from and subordinate to the Father. What is declared as ‘orthodox’ in Theodosius’ edict was not orthodox when the Controversy began:

In the traditional account of the Arian Controversy, the Trinity doctrine was orthodoxy when the Controversy began. However, we know today that the traditional account is a complete travesty. The 20th century has produced much revisionary scholarship on the Trinitarian and Christological disputes of the fourth century.” (LA, 11) 1LA = Lewis Ayres Nicaea and its legacy, 2004

One year later, the Council of Constantinople in 381 issued a creed that is very similar to the creed of 325 but still identifies the “one God” as the Father.

Nevertheless, in 380, Theodosius outlawed all non-Trinitarian forms of Christianity and ruthlessly exterminated all opposition to the Trinity doctrine. He expelled their bishops, forbade them to meet and preach, and gave their churches to Trinitarian congregations. He was responsible for the first official executions of Christian ‘heretics’. [Jones 1964, p. 164] Religious persecution was part of the Roman culture. Roman emperors always used religion to strengthen the unity of their vast empire and persecuted religions that threatened unity.

The West became Germanic-dominated.

However, the Germanic peoples (called ‘barbarians’ by the Romans) remained anti-Trinitarian. Huge numbers of Germanic peoples migrated into the territory of the Empire over the previous century. Many of them were recruited into the Roman army, to such an extent that the Imperial forces became dependent on Germanic soldiers. They were also appointed to top positions in the military. Since Roman generals always were very influential in the Roman Empire, this put these ‘barbarians’ in a very strong position.

Theodosius was the last Roman emperor to rule the entire Empire. Soon after he died in 395, Germanic people effectively had control of the Western Roman Empire. Nevertheless, the Graeco-Roman population still treated them as second-class citizens. Therefore, to demand equal rights and permanent residency in the empire, the Germanic people revolted against the severe conditions of their tenure in the Roman Empire. They sacked Rome in 410 and again in 455. (See Fall of the Roman Empire.)

Although they dominated the Western Empire already from the beginning of the 400s (the fifth century), they tolerated figurehead Western Roman Emperors until 476, when Odoacer—an Arian Germanic chieftain—deposed the last Western Roman Empire and soon conquered the whole of Italy.

They then divided the territory of the Western Empire between the Germanic tribes. However, these tribes continued to function as part of the Roman Empire. In name at least, they were subject to the Emperor in Constantinople. For these reasons, historians today prefer to refer to the Transformation of the Western Roman Empire; rather than to its Fall. It was a slow process over decades and even centuries during which the Germanic people wrestled control of the Western Empire from the Romans. 

The ‘Germans’ were ‘Arians’.

Theodosius had exterminated opposition to the Trinitarian doctrine from among the Roman people. But the Germanic nations were converted by the efforts of the church in the time before Theodosius when the church majority was ‘Arian’. These Germanic people, therefore, were ‘Arian’. Consequently, the Western Roman Empire was once again ‘Arian’. dominated.

The term ‘Arian’ is a serious misnomer because Arius was an insignificant theologian. He did not leave a school of disciples. Today, we use the term ‘Arian’ for all opposition to the Trinity doctrine because Athanasius invented to term to insult his opponents by labelling them with an already discredited theology. This article continues to use the term ‘Arian’, not to refer to the theology of Arius, which was one specific anti-Trinitarian theology, but to refer to all opposition to the Trinity doctrine.


United with the Roman Empire.

The Roman Church survived throughout this period. There are at least two reasons why we might have expected the Church in Rome to perish with the demise of the Western Empire. Firstly, as stated, while the Roman Church was Trinitarian, the Germanic peoples were ‘Arian’. 

Secondly, the Church in Rome was part of the government of the Roman Empire. After Emperor Constantine legalized Christianity in 313 AD, the church became united with the state. Division of church and state was not a reality. The emperors decided which religions were legal and they effectively became the head of the church. He had the final say concerning controversies in the church and with respect to whether bishops should be exiled and re-admitted. The view of the emperor, and whoever had the ear of the emperor, determined the theology of the church. For example:

Emperor Constantine had a huge role in the decisions of the Council of Nicaea. He called the council, presided over it, guided the discussions, proposed and enforced the important word Homoousios, and exiled all bishops who refused to sign the Creed. The preference of the emperor allowed the inclusion of the term homoousios.

When Theodosius I became emperor in 379, the imperial capital was solidly Arian. But he almost immediately outlawed all non-Trinitarian forms of Christianity, exiled Arian bishops, and excluded Arians from the Council of 381. (See Theodosius.)

As a consequence of the elevated status of the church, Christianity became wealthy and the religion of any ambitious civil official.

The ‘Germans’ tolerated the Roman Church.

Given the unity of the Roman Church and the Roman Empire, one might have expected the Germanic peoples to oppose the Roman Church in the West. However, the Roman Church survived in the West. The new Arian rulers in the Western Empire allowed the Roman Church (the Church of the Roman Empire) to co-exist unimpeded. The Germanic people, after they took control of the Western Empire, intended to remain part of the Roman Empire and tolerated the Roman Church because it was an official part of the Roman system of government; accountable to the emperor. The Germanic people voluntarily—in name at least—subjected themselves to the Roman Emperor, who reigned from the east. Consequently, Arianism and the Trinitarian Church of the Roman people existed side by side. The Jewish Encyclopaedia describes the situation:

“Most Germanic peoples—such as the eastern and western Goths, as also the Franks, the Lombards, the Suevi, and the Vandals—were baptized into Arian Christianity. These tribes settled in widely spread districts of the old Roman empire. A large number of Jews, already resident in those lands, fell under Arian domination. In contrast with the domination of the orthodox church, the Arian was distinguished by a wise tolerance and a mild treatment of the population of other faiths. This conduct was traceable to some degree to certain points of agreement between the Arian doctrine and Judaism. The very insistence upon the more subordinate relationship of the Son to the God-father is much nearer to the Jewish doctrine of the Messiah than to the conception of the full divinity of the Son, as enunciated at Nicaea.” (Kohler, Kaufmann; Krauss, Samuel. “ARIANISM”. Jewish Encyclopedia. Kopelman Foundation.)

The tolerance of the Arian tribes towards other religions resulted in entirely distinct Arian and Trinitarian systems of churches and bishops in the previous Western Empire. 

Although the Arian Germanic tribes were generally tolerant towards Nicene Christians, the Vandals in North Africa tried to force their Arian beliefs on their North African Nicene subjects, exiling Nicene clergy, dissolving monasteries, and exercising heavy pressure on non-conforming Nicene Christians. This matter will become important when we read of Emperor Justinian’s efforts in the sixth century to regain control of the Western Empire, for the first ‘barbarian’ nation that he attacked was the Vandals.

The Roman Church became stronger.

Actually, instead of perishing, the Church in Rome grew in strength after the ‘barbarians’ wrestled control of the western provinces from the original Graeco-Roman population (Britannica). The reasons include the following:

(A) The Church had a strong, centralized organization: The pope in Rome is the head of the Church. All clergy, including bishops and priests, fell under his authority. Bishops supervised priests; the lowest-ranking members of the clergy. For most people, local priests served as the main contact with the Church.

(B) At the same time, after the fall of the Western Roman Empire, there was no single state or government that united all people who lived on the European continent. The transformation of the Western Roman Empire in the fifth century was a time of great political chaos and warfare and the well-organized church became the only stabilizing force. As secular governments came and went, the Papacy remained. The church was a stable force during an era of constant warfare and political turmoil.

(C) The Church also bonded people together. It gave a sense of communal identity. At the local level, the village church was a unifying force in the lives of most people. It served as a religious and social center. Religious holidays, especially Christmas and Easter, were occasions for festive celebrations.

Arians converted to the Roman Church.

One consequence of the growing strength of the Roman Church was that the Germanic peoples converted to the Trinity doctrine, rather than to Arianism. The Franks were the first to convert.

The Franks and the Anglo-Saxons also were Germanic peoples but never were Arians. They entered the Western Roman Empire as Pagans.

The Franks were the first to convert. In 496, Clovis, king of the Franks, converted to Nicene Christianity—as opposed to the Arianism of most other Germanic tribes. Consequently, sometime between 496 and 508, Clovis I forcibly converted the Franks to Christianity. (So much for religious freedom!) This led to widespread conversion among the Frankish peoples across what is now modern-day France, Belgium, and Germany.

Æthelberht of Kent did the same for the Anglo-Saxons (see also Christianity in Gaul and Christianisation of Anglo-Saxon England). 

Visigothic Spain was Arian until 589. 

The Lombards were Arians until the 7th century.


The religious preferences of the Roman Emperors determined the Christology of the church. The current article refers to the roles which Constantine and Theodosius played. As the next article will show, in the sixth century, Emperor Justinian gave Arianism a death wound and it died during the subsequent Byzantine Papacy. The fact that the church today is dominated by the Trinity doctrine is the direct result of decisions taken by Roman Emperors.



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    LA = Lewis Ayres Nicaea and its legacy, 2004