For around 450 years, from around 55 BCE to around 410 CE, the southern part of the Netherlands was integrated into the Roman Empire. During this time the Romans in the Netherlands had an enormous influence on the lives and culture of the people who lived in the Netherlands at the time and (indirectly) on the generations that followed.

During the Gallic Wars, the Belgic area south of the Oude Rijn and west of the Rhine was conquered by Roman forces under Julius Caesar in a series of campaigns from 57 BCE to 53 BCE. He established the principle that this river, which runs through the Netherlands, defined a natural boundary between Gaul and Germania magna. But the Rhine was not a strong border, and he made it clear that there was a part of Belgic Gaul where many of the local tribes were "Germani cisrhenani", or in other cases, of mixed origin. The approximately 450 years of Roman rule that followed would profoundly change the area that would become the Netherlands. Very often this involved large-scale conflict with the "free Germans" over the Rhine.