Which of the following groups is associated with weakening the Roman Empire?

The Visigoths played a significant role in the decline of the Roman Empire, particularly during its later stages. As a Germanic tribe, they were one of the various groups that took advantage of the empire's weakening structure due to internal strife, economic difficulties, and political corruption. The Visigoths famously crossed the Danube River in 376 CE seeking refuge from the Huns and ended up settling in Roman territory. Their relationship with Rome became increasingly hostile, culminating in the sack of Rome in 410 CE under their leader Alaric. This event symbolized the vulnerabilities of the Roman Empire and illustrated how foreign invasions contributed to its gradual collapse. The Visigoths subsequently established their own kingdom in the territory of what was once Roman land, further demonstrating their impact on the empire's fragmentation and eventual downfall.

The other groups mentioned do not have the same direct association with weakening the Roman Empire. The Byzantines were part of the Eastern Roman Empire, continuing the legacy of Roman governance and culture long after the fall of the West. The Carthaginians were one of Rome's primary adversaries in the Punic Wars, but they were vanquished well before the empire's decline, and their defeat actually led to Roman expansion.