When Alaric I and his Visigoths sacked Rome in 410 CE, the event was not just a military disaster; it was a catalyst for a massive displacement of wealth and intellectual capital. As Rome fell, wealthy aristocratic families fled to North Africa, specifically Carthage, bringing their gold, their libraries, and their search for spiritual security.
Alaric was a follower of Arian Christianity (the belief that Jesus was a created being, subordinate to the Father). To a modern student, this looks like a "wrong" version of Christianity. To a historian, it looks like a Political Identity Marker.
By adhering to Arianism, Alaric and the Goths created a "National Church" that distinguished them from the Roman citizens they governed. The condemnation of Arianism by emperors in Constantinople and Rome was not merely about the nature of the Trinity; it was about Imperial Sovereignty. If the Emperor is the head of the Nicene Church, then any one who is Arian is, by definition, a political rebel.
The Refugee Crisis of 410: The flight of the Roman elite to Carthage created a sudden "market" for theological leadership. Figures like Pelagius, fleeing the chaos of Italy, found themselves in Carthage not just as refugees, but as competitors for the attention (and the patronage) of these wealthy displaced families.