Who was the first ruler of the Rhineland?

The first ruler of the Rhineland can be traced back to Charlemagne, who was a pivotal figure in the history of Europe during the late 8th and early 9th centuries. As the King of the Franks and later Emperor of the Carolingian Empire, Charlemagne significantly expanded his territory, which included the Rhineland region. His reign marked the beginning of a centralized rule that helped lay the foundations for what would later become the Holy Roman Empire. Charlemagne's efforts in administration and governance in the region set the stage for the political landscape that followed.

While other historical figures like Julius Caesar, Otto the Great, and Frederick Barbarossa each played significant roles in European history and influenced the territories they ruled, they did so in different contexts and periods. Julius Caesar was instrumental during the Roman conquest of Gaul, which did involve parts of what is now Germany, but he did not establish rulership over the Rhineland in the way that Charlemagne did as a later kingdom. Otto the Great and Frederick Barbarossa were influential rulers in their own right, contributing to the strength of the Holy Roman Empire, particularly in the 10th and 12th centuries, but their rule came after Charlemagne's establishment in the region.