structural:summarization
Divided empire, after 840

Charlemagne had several sons, but only one survived him. This son, Louis the Pious, followed his father as the ruler of a united empire. But sole inheritance remained a matter of chance, rather than intent. When Louis died in 840, the Carolingians adhered to the custom of partible inheritance, and after a brief civil war between the three sons, they made an agreement in 843, the Treaty of Verdun, which divided the empire in three:

Subsequently, at the Treaty of Mersen (870) the partitions were recast, to the detriment of Lotharingia. On 12 December 884, Charles the Fat (son of Louis the German) reunited most of the Carolingian Empire, aside from Burgundy. In late 887, his nephew Arnulf of Carinthia revolted and assumed the title as King of the East Franks. Charles retired and soon died on 13 January 888.

Odo, Count of Paris was chosen to rule in the west, and was crowned the next month. At this point, West Francia was composed of Neustria in the west and in the east by Francia proper, the region between the Meuse and the Seine. The Carolingians were restored ten years later in West Francia, and ruled until 987, when the last Frankish King, Louis V, died.

West Francia was the land under the control of Charles the Bald. It is the precursor of modern France. It was divided into the following great fiefs: Aquitaine, Brittany, Burgundy, Catalonia, Flanders, Gascony, Gothia, the Île-de-France, and Toulouse. After 987, the kingdom came to be known as France, because the new ruling dynasty (the Capetians) were originally dukes of the Île-de-France.

Middle Francia was the territory ruled by Lothair I, wedged between East and West Francia. The kingdom, which included the Kingdom of Italy, Burgundy, the Provence, and the west of Austrasia, was an unnatural creation of the Treaty of Verdun, with no historical or ethnic identity. The kingdom was split on the death of Lothair II in 869 into those of Lotharingia, Provence (with Burgundy divided between it and Lotharingia), and north Italy.

East Francia was the land of Louis the German. It was divided into four duchies: Swabia (Alamannia), Franconia, Saxony and Bavaria; to which after the death of Lothair II were added the eastern parts of Lotharingia. This division persisted until 1268, the end of the Hohenstaufen dynasty. Otto I was crowned on 2 February 962, marking the beginning of the Holy Roman Empire (translatio imperii). From the 10th century, East Francia became also known as regnum Teutonicum (" Teutonic kingdom" or " Kingdom of Germany "), a term that became prevalent in Salian times. The title of Holy Roman Emperor was used from that time, beginning with Conrad II.