How did Theodosius I limit further invasions by Teutonic groups?

To limit further invasions by Teutonic groups, Theodosius I employed a strategy that combined diplomatic accommodation with firm displays of imperial authority. Recognizing that the barbarians who had entered the provinces since 375 could no longer be expelled solely by force, he sought new possibilities for coexistence.1

His primary method for managing existing threats was the conclusion of a treaty of alliance, or foedus, with the Visigoths in 382. Under this arrangement, the Goths were granted land for settlement between the lower Danube and the Balkan mountains, allowing them to remain an autonomous unit while pledging military assistance to the empire.1

However, this policy of accommodation was not intended to be a universal precedent. Theodosius took strict measures to prevent further unauthorized incursions and consistently maintained a clear stance regarding Roman superiority over the barbarians. By integrating these groups into the military structure as foederati (allies), he aimed to bolster Roman military strength and cultivate wasteland, while simultaneously ensuring that no doubts arose regarding the authority of the Roman Empire over these populations.12