Heresies are like weeds. They keep coming back. The thing is, they come back in different guises. In the fourth century Arianism was part of the great debate over the divinity of Christ and therefore the definition of the Holy Trinity.
In the course I am teaching at Avila Institute on How St Benedict Changed the World we spent part of Monday night’s first session discussing the heresy of Arianism. The heresy began with the teaching of Arius in the mid third century, and spread throughout the Empire. Missionaries from the Eastern part of the empire went North and the Gothic tribes were converted to Arianism. In our discussion of Benedict we pointed out how, when he was a young man studying in Rome around the year 500, Italy was ruled by the Gothic king Theodoric the Great who was Arian.
Arianism developed into not just a theological problem, but a major schism. The Arians had their own churches, their own bishops and their own temporal powers, like Theodoric, supporting them. At the core of Arianism was a denial of Nicene christology. Put simply, they believed that Jesus was the “Son of God” but he was not the second person of the holy and undivided Trinity who took human flesh of his blessed mother. He was, instead, a created being–a demi god and therefore subordinate to God the Father.