A category of people who flourished from about 750 to 12 B.C. During this time, the Celts were the most powerful group in central and northern Europe. Although the Celts were composed of many different tribes, they shared similar languages, technology, customs, artistic styles, and beliefs. By A.D. 60, their power had been destroyed by the Romans. After that, only the Celtic tribes in the more remote areas of Europe, such as the British Isles, survived.