The History of the Decline and Fall of the Roman Empire / Table of Contents with links in the HTML file to the two Project Gutenberg editions (12 volumes) · Chapter 121
Battle of Adrianople
In 378 CE, Emperor Valens was defeated and killed by Gothic forces at Adrianople, marking the first time a Roman emperor had fallen in battle against barbarians in centuries and exposing the empire's military vulnerability.
Outcome
The defeat forced Rome to accept Gothic settlement within imperial borders as federates, fundamentally altering the relationship between Romans and barbarians.