The' 'Celts is an umbrella term for a widespread group of nations in ancient times, their lands ranging from the British Isles to Galatia in Asia Minor (Anatolia). Among the Celts were many peoples, including the Gauls, the Britons, the Picts (Scotland), the Celtiberians and Asturians (Spain), the Belgae (Low Countries and western Germany), and the Boii (northern Italy and eastern Europe). And also the Galatians, who would migrate to Turkey in the Third Century BCE. Although they were fierce warriors that threatened the classical world and they even sacked Rome on occasion, the Celtic peoples were nevertheless overrun and assimilated by Mediterranean and later Germanic cultures.
Before the invasion of Britain, the Celts (also known as "Keltoi") territory covered the islands and the western part of the Rhine.