On this day...

On this day, March 28 of the year 845, a huge Viking fleet attacked Paris. They were led by chieftain Ragnar (Reginherus in Frankish sources), who is traditionally identified as the legendary Ragnar Lothbrok.
Ragnar's fleet, consisting of 120 Viking ships carrying thousands of men, reached Paris after having defeated the French army trying to stop them along the river Seine. After plundering and occupying Paris, the Vikings withdrew when they had been paid a huge ransom of 2570 kilograms (5665 lbs) of silver and gold from Charles the Bald, the French king.
The attack is believed to be an act of revenge since Ragnar had been given land and the favor of the king 4 years earlier. The king had betrayed him and Ragnar had lost the land.