Barbarians were people who came from anywhere outside of Greece and later Rome. The term is often used to refer to the Germanic and Slavic tribes that attacked Rome during its decline.
According to the Online Etymology Dictionary, "barbar" was probably intended to mimic the sound of a foreign language, and ancient Greeks applied it to anyone from a different culture. Although it was originally a neutral term, it later took on negative associations. Barbarians were seen as primitive and violent. The Romans used the term to describe the people they were trying to conquer, especially those who resisted them. For them, the term had more complex meanings and was not always an insult.