Austrasia

Austrasia was a historical region and the northeastern realm within the core of the Frankish State during the Early Middle Ages, centering on the regions between Meuse, Moselle, Middle Rhine and the Main rivers. It included the original Frankish-ruled territories within what had been the northernmost part of Roman Gaul. It also stretched beyond the old Roman borders on the Rhine into Frankish areas which had never been formally under Roman rule. It represented the northeastern part of the Frankish realm, founded by the Merovingian king Clovis I (r. 481–511), while the more Romanized regions to its west came to be known as Neustria.

Austrasia and Neustria along with Aquitaine and Burgundy to their south, formed the basis of subdivisions into which the Frankish Merovingian dynasty divided their realm. In the 8th and 9th centuries, their successors in the Carolingian dynasty, had their original powerbase in Austrasia. These two Frankish dynasties did not always have a single ruling monarch over the whole Frankish realm, and already by 561, Austrasia was ruled as a separate kingdom within the Frankish realm by the Merovingian king Sigebert I (561–575). Kings often allowed different family members to rule sub-kingdoms, and these were sometimes in conflict with each other, despite the underlying continuity of the overall Frankish state.

In the 843 Treaty of Verdun Austrasia was divided into two parts, with the parts east of the Rhine becoming a single East Francia kingdom together with the non-Frankish lands of the Saxons, Thuringians, Bavarians and Allamani, while in Gaul west of the Rhine forming the northernmost part of a new kingdom of Middle Francia which stretched to Italy. This kingdom was further divided in the Treaty of Prüm (855) and Austrasia became the realm of king Lothair II, whose name gave rise to the new term Lotharingia. Lotharingia was divided by the Treaty of Meerssen (870), but reunited by the Treaty of Ribemont (880), which also brought it under east Frankish rule. During the 9th century, Austrasia was still considered as one of the main regions (stem lands) within the Carolingian Empire, surrounded by Alamannia (to the south), Bavaria (to the south-east), Thuringia (to the north-east), and Saxony (to the north), as attested by the Royal Frankish Annals, and the Annals of Saint Bertin, that mentions not only Austrasia, but also Autrasians.

In time, central Austrasia was more frequently designated as Lotharingia, that became the prevailing term for those regions, while eastern parts of Austrasia came to be known as Franconia.