The Pre-Roman Iron Age of Northern Europe (5th/4th–1st century BC) was the earliest part of the Iron Age in Scandinavia, northern Germany, and the Netherlands north of the Rhine River. These regions feature many extensive archaeological excavation sites, which have yielded a wealth of artifacts. Objects discovered at the sites suggest that the Pre-Roman Iron Age cultures evolved without a major break out of the Nordic Bronze Age, but that there were strong influences from the Celtic Iron-Age Hallstatt culture in Central Europe. During the 1st century BC, Roman influence began to be felt even in Denmark.