The Duchy of Thuringia was an eastern frontier march of the Merovingian kingdom of Austrasia, established about 631 by King Dagobert I after his troops had been defeated by the forces of the Slavic confederation of Samo at the Battle of Wogastisburg. It was recreated in the Carolingian Empire and its dukes were appointed by the king until it was absorbed by the Saxon dukes in 908. From about 1111/12 the territory was ruled by the Landgraves of Thuringia as Princes of the Holy Roman Empire. When Frederick IV, the last independent ruler of Thuringia died in 1440, the territory passed to his nephew, the Saxon elector Frederick II.

Austrasia was a territory which formed the north-eastern section of the Kingdom of the Franks from the 6th to 8th centuries, ruled by the Frankish Merovingian and Carolingian dynasties during the Early Middle Ages. It was centred on the Meuse, Middle Rhine, and the Moselle rivers, and was the original territory of the Franks, including both the so-called Salian Franks and Ripuarian Franks, which Clovis I, King of the Franks (481–511) conquered after first taking control of the bordering part of Roman Gaul, which is sometimes described in this period as Neustria.