Why were Germans allowed to cross the Roman borders of the Roman Empire?

Answer 1

First of all it was not the Germans. Germany and the Germans did not exist back then. It was the Germanic peoples. Germanic is a linguistic group which includes German, Dutch, Danish, Swedish, Norwegian and English. These Germanic peoples were the ancestors of the peoples who speak these modern languages.

The Franks who lived around the mouth of the river Rhine were allowed to settle in Holland south of the Rhine and in Belgium because they were short of land and they were allies of the Romans who supplied troops and cavalry to them.

The Visigoths asked the Romans to be allowed to settle in the lower Danube area of the Roman Empire because they wanted to escape the Huns who were conquering Eastern Europe. Emperor Valens granted this in 376.

The Ostrogoths settled in Pannonia (eastern Austria and western Hungary) while the Romans lost control of this area to the Huns. After the collapse of the Hun Empire the Romans and the Ostrogoths became allies and the Ostrogoths were allowed to stay.

Other smaller Germanic peoples were allowed to settle in smaller areas of the Roman Empire because they needed land and because they could become suppliers of soldiers for the Romans.

Several Germanic peoples who crossed the frontiers of the western part of the Roman Empire in 406 AD, the Vandals, the Sueves, and the Burgundians (and the Alans who were an Iranian-speaking people) were invaders. The western part of the Roman Empire fell under the weight of this Germanic invasion. The invaders eventually took over all the lands of this part of the Roman Empire except for Italy. This invasion was more than just a military action. It was also the migration of whole peoples. There was what historians called the Migration Period. Peoples form northern Europe migrated south into central and eastern Europe in search for new lands for settlement. This had created pressure on the European frontiers of the Roman Empire for the previous 250 years. There had been attempted invasions (which the Romans repelled) by Germanic peoples form central Europe, who probably were being squeezed by the expansion of the Goths in eastern Europe. Things got much worse in the late 4th century BC when the peoples north of the Roman Empire became squeezed by the expansion of the empire of the Huns into eastern and central Europe. This played a key role in the mentioned invasion of 406.

The Saxons, Angles and Jutes from northern Germany and the Frisians from northern Holland (all Germanic peoples) migrated to Britain in waves and took over this island. The Roman legions in Britannia were withdrawn to deal with problems in the continent or were redeployed there by usurper emperors.