The Battle of Leuven is fought in September 891 between the Franks and the Vikings, essentially ending the Viking invasions in the Low countries.
The existence of this battle is known due to the Annales Fuldenses.
"Who controls the past controls the future: who controls the present controls the past...Every record has been destroyed or falsified, every book has been rewritten, every picture has been repainted, every statue and street and building has been renamed, every date has been altered."