Translated from Baidu Encyclopedia: In 797 AD, the Vikings invaded Caroline Empire for the first time. Under the rule of Charlemagne, the Viking invasion was quickly repelled. In 834 AD, the Vikings robbed Dores Port, the financial and commercial center of Caroline Empire, and went north along the Seine River, plundering Rouen and other places along the way. After the death of Louis I, the son of Charles the Great, Caroline's empire was divided into three parts, forming the embryonic form of Germany, France and Italy. Caroline dynasty began to split and gradually declined. With the disintegration of Caroline dynasty, the vikings invaded Antwerp in 836 AD, plundered Rouen again in 84 1 year, and captured Paris under the leadership of the famous ragnar Lodblock in 845, and carried out large-scale plunder. The West Frankish Kingdom was forced to make peace and paid 7,000 Riffle worth of "Danish gold" to let the Vikings leave. However, this is only the beginning, and the Franks will pay the Vikings a huge "Danish gold" of 12 times in the following days. In 864 AD, under the order of Charles, the bald king of West Frank, two bridges were built in Paris, one across the Seine and the other on the island of Daisy. From 885 to March 886, the Vikings plundered Paris for the last time and ended in failure.