Louis (also Ludwig or Lewis) "the German" (c. 810[1] ? 28 August 876), also known as Louis II, was a grandson of Charlemagne and the third son of the succeeding Frankish Emperor Louis the Pious and his first wife, Ermengarde of Hesbaye.
He received the appellation 'Germanicus' shortly after his death in recognition of the fact that the bulk of his territory had been in the former Germania. The epithet 'the German' is the sign of an early national historical reinterpretation. The epithet itself emerged only in the 18th century. Thus, the nickname is anachronistic.
Louis II was made the King of Bavaria from 817 following the Emperor Charlemagne's practice of bestowing a local kingdom on a family member who then served as one of his lieutenants and the local governor. He ruled in Regensburg, the old capital of the Bavarii. When his father, Louis I (called the pious), partitioned the empire toward the end of his reign in 840, he was made King of East Francia, a region that spanned the Elbe drainage basin from Jutland southeasterly through the Thuringerwald into modern Bavaria from the Treaty of Verdun in 843 until his death (wikipedia)