East Francia (Latin: Francia orientalis) or the Kingdom of the East Franks (regnum Francorum orientalium) was a successor state of Charlemagne's empire and precursor of the Holy Roman Empire. Until 911 it was ruled by Carolingian dynasty. It was created after the 840-43 civil war between Charlemagne's grandchildren which ended with the Treaty of Verdun which divided the former empire into three kingdoms. By the middle of the 10th century, the kingdom had become usually referred to as Kingdom of Germany or the Holy Roman Empire, therefore making it the earliest stage in the development of the modern German state.
The east–west division, enforced by the German-Latin language split, "gradually hardened into the establishment of separate kingdoms", with East Francia becoming the Kingdom of Germany and West Francia the Kingdom of France.
In August 843, after three years of civil war following the death of emperor Louis the Pious on 20 June 840, the Treaty of Verdun was signed by his three sons and heirs. The division of lands was largely based on the Meuse, Scheldt, Saone and Rhone rivers. While the eldest son Lothair I kept the imperial title and the kingdom of Middle Francia, Charles the Bald received the West Francia and Louis the German received the eastern portion of mostly Germanic-speaking lands of Duchy of Saxony, Austrasia, Alamania, Duchy of Bavaria, and March of Carinthia.