When and why did trade by ship begin along the Rhine?

The Rhine has been used for trade and transportation since the Neolithic era, and trade by ship along the Rhine most likely began in the same time period. The river provided an easy and efficient means of transporting goods between the various settlements and cities that were located along its banks, and it also served as a trade route for merchants from across Europe. The Rhine was a major trade route during the Roman Empire, and it continued to be an important trade route after the fall of the empire. In the Middle Ages, the Rhine was one of the most important trade routes in Europe, and it was used to transport goods such as grain, wine, and spices from the Low Countries to the rest of Europe.