By the late Bronze Age, the Urnfield culture (c. 1300 BC to 750 BC) had replaced the Bell Beaker, the Unetice and Tumulus cultures in central Europe. The Hallstatt culture, which had developed from the Urnfield culture was the predominant Western and Central European culture from the 12th to 8th centuries BC and during the early Iron Age (8th to 6th centuries BC). The people, who had adopted these cultural characteristics are regarded as Celts. How and if the Celts are related to the Urnfield culture remains disputed. However, Celtic cultural centers developed in central Europe during the late Bronze Age (circa 1200 BC until 700 BC). Some, like the Heuneburg at the Danube, grew to become important cultural centres of the Iron Age in Central Europe, that maintained trade routes to the Mediterranean. In the 5th century BC the Greek historian Herodotus mentioned a Celtic city at the Danube - "Pyrene", that historians attribute to the Heuneburg. Beginning around 700 BC, Germanic peoples from southern Scandinavia and northern Germany expanded south and gradually replaced the Celtic peoples in Central Europe.