Louis the German

Louis the German is conventionally regarded as the founder of the East Frankish kingdom, the political ancestor of medieval Germany. The third son of Emperor Louis the Pious, he was assigned Bavaria in the succession arrangement of 817 and governed it from the mid-820s, building a regional power base east of the Rhine. Like his brothers, he was drawn into the rebellions against his father in the 830s, and after the emperor's death in 840 he joined Charles the Bald against their elder brother Lothair I.

The brothers' victory at Fontenoy in 841 was followed by the Strasbourg Oaths of 842, sworn by Louis in the Romance vernacular and by Charles in Old High German so that each other's followers could understand them, a document of lasting linguistic importance. The Treaty of Verdun in 843 confirmed Louis in the lands east of the Rhine, together with the districts of Mainz, Worms, and Speyer on the west bank.

His reign of more than three decades was occupied with campaigns against the Slavs on his eastern frontier, including a prolonged contest with Rastislav of Moravia, and with intermittent ambitions in the west. In 858 he invaded West Francia at the invitation of discontented nobles but failed to displace Charles the Bald. The Treaty of Meerssen in 870 brought him the eastern portion of Lotharingia, including Aachen, after the death of their nephew Lothair II.

Louis married Emma, a member of the Welf family and sister of his stepmother, the empress Judith. He divided his realm among his three sons: Carloman received Bavaria, Louis the Younger received Franconia and Saxony, and Charles the Fat received Alemannia. The marriage of Louis the Younger to Liutgard, a daughter of the Saxon Liudolfing house, created an early bond between the Carolingians and the family that would later rule East Francia as the Ottonian dynasty. Louis the German died at Frankfurt in August 876 and was buried at the abbey of Lorsch. His kingdom, unlike the western realm, passed intact to his sons, and its institutions outlasted the dynasty itself.