A barbarian is someone who is perceived to be either uncivilized or primitive. The term is usually applied as a generalization based on a popular stereotype, and can be used to describe people from foreign lands whose language and customs differ from the speakers. Historically, the term has been used to describe people living outside the pale of the Roman Empire and its civilization, especially the northern nations that overthrew them. The word "barbarian" is derived from the ancient Greek word βάρβάρος, which was used to describe all foreigners, including the Romans. Over time, the meaning of the word changed somewhat when Romans used it to refer to all foreigners, especially the wide variety of people who were encroaching on their borders. Some barbarians pillaged the Roman Empire while others became its allies. The term "barbarian" did not have a negative meaning for everyone in the Roman Empire, and some people regarded barbarians as loving each other while the Romans persecuted each other. In modern usage, the term "barbarian" can be used to describe a person from an alien land, culture, or group believed to be inferior, uncivilized, or violent.