843 – Treaty of Verdun
About 1,5 years previously with the Oaths of Strassbourg in 842, Louis the Pious’ sons Charles the Bald and Louis the German pledged their alliance against their brother Lothair I, the Holy Roman Emperor. Their alliance made Lothair listen to them and negotiate. This resulted in the treaty of Verdun whereby the Carolingian empire was divided into three kingdoms. Lothair remained emperor in all but name.
For some food for thought, see this video and make up your own mind to agree or disagree!
955 – Battle of Lechfeld
Otto I, the Holy Roman Emperor fought off the Magyars who had come as far as Bavaria. It was a devastating victory that also stopped further invasions of the nomadic tribes into (north)western Europe.
Here is another of Baz’ excellent battle videos on YouTube to give the context (really, the whole context!) of the battle: