About 1000 BC, Greek and Phoenician colonists were settling all around the Mediterranean Sea, and bringing more and more West Asian and Greek culture to Northern Europe. Northern Europeans traded tin and furs, wood, salt, and slaves for wine, olive oil, Greek pottery, glass beads, linen cloth, African ivory, and iron knives and swords. The chiefs used these luxuries and the swords to get more and more control over their people. The resulting culture, known as the Hallstatt culture after a salt mining area of Austria that got rich from selling salt, spread all across Europe in the 700s BC.
Beginning around 100 BC, the Romans began not just to trade, but to conquer the people of northern Europe. By 150 AD, the Roman Empire controlled Britain, France, Belgium, much of Germany, Spain, Portugal, and the Balkans (as well as Greece and Italy). North of the Danube River, most of Central Europe was still independent, but they were more and more influenced by Roman traders and Roman ideas.
Many Northern European men, from both sides of the Roman border, fought in the Roman army. Many Northern European houses, bridges, and roads were built in the Roman style. Northern European people often wore Roman jewelry, and sometimes wore Roman clothing, and prayed to Roman gods. In the 200s and 300s AD, Roman missionaries converted many people in Northern Europe to Arian Christianity.
But the power of Rome was already ending. When the Sassanians began to attack Rome’s eastern border about 220 AD, the Northern Europeans attacked at the same time, and the Romans had to split their army between the two wars. The Romans couldn’t afford to keep fighting two wars at the same time, and gradually the Northern Europeans, fighting as soldiers for Rome, noticed that there really wasn’t any strong Roman army anymore. At the same time, a new invasion from Central Asia began: the Huns were sweeping over northern Europe. To get away from the Huns, the people of Northern Europe started to move into the Roman Empire. In 376 AD, the Visigoths crossed the Danube river; in 409 AD the Vandals, Alans, and Sueves crossed the Rhine river, and the Franks and Ostrogoths soon followed them.