Charlemagne died in 814 and the throne passed to his son Louis the Pious. However, soon three sons of Louis pious Karl Lysy, Louis German and Lothar – began to seek from the father of the partition of the empire. In order to calm them down, Louis the Pious in 817 divided the empire between his sons. But he did not achieve peace. The war began, the sons defeated the father.
After the death of Louis the Pious, the feud broke out with renewed vigor. Two younger brothers – Louis German and Karl Bald did not want to recognize the imperial title of Lothar. The war began. In 842, Louis the German and Karl Bald met in Strasbourg and vowed to work together in the fight against Lothar. The Strasbourg oath was pronounced in two languages - Romanesque and Teutonic. This indicated the formation of new nationalities in the Carolingian Empire, in particular French and German.
IX century. Frankish chronicler Nitgaard about the adoption of the Strasbourg oath
on February 14, Louis and Karl gathered in a city that was once called Argentarpia, and today in common parlance is called Strasbourg, and they proclaimed the following oaths, Louis in Romance, and Karl in Teutonic. The first to take the oath was Louis, because he was the eldest: “Out of love for the Lord, for the sake of Christian and our common salvation, henceforth and in the future, as far as the Lord God will give me intelligence and strength, I will support my Karl’s marriage and military assistance, and every other business “as every man must truly support his brother, if he answers me that way, and from Lothar I will not accept a single condition that will certainly harm my brother Charles.” When Ludovic finished, Charles proclaimed the same oath in the Teutonic language.
Lothar was forced to concede. In August 843, the brothers concluded a treaty in Verdun, according to which the empire created by Charles the Great was divided into three parts. Under the terms of the Treaty of Verdun, the youngest of the brothers, Karl Lysom, got lands west of the Rhine, which became the basis of the territory of the future France. To the middle brother, Louis German, the lands east of the Rhine have departed – the territory of the future Germany. The eldest of the brothers, Lothar, retained the title of emperor, and also received Italy and a long strip of land from the mouth of the Rhine to the mouth of the Rhone. Later, this territory was called Lorraine. The signing of the Verdun Treaty laid the foundations of the modern European states of Italy, Germany and France.