The Central region
Originally an eastern frontier march of the Merovingian kingdom of Austrasia (631) it was elevated to the status of duchy during the Carolingian era; its dukes being appointed by the king until it was absorbed by the Saxon dukes in 908. Known as the limes Sorabicus, or Sorbian March, in 849 it was placed under a duke named Thachulf. In the Annals of Fulda his title is dux Sorabici limitis, "duke of the Sorbian frontier", but he and his successors were commonly known as duces Thuringorum, "dukes of the Thuringians".
As duke, Thachulf had military command over the counts with lands bordering the Sorbs. According to the Annales Fuldenses, in 858, a Reichstag held at Frankfurt under Louis the German sent three armies to the eastern frontiers to reinforce the submission of the Slavic tribes. Carloman was sent against Great Moravia, Louis the Younger against the Obodrites and Linones, and Thachulf against the Sorbs, who were refusing to obey him. The armies of Carloman and Louis set out in July, but it is uncertain if Thachulf ever undertook a campaign, as the Sorbs rose in rebellion late in that year and do not appear to have been restless beforehand.
Thachulf died in the summer of 873 which was immediately followed by the revolt of the Sorbs, Siusli, and their neighbours. The revolt was not put down until Liutbert and Radulf, Thachulf's successor, campaigned in January 874.
In 880, King Louis replaced Radulf with Poppo, perhaps a kinsman. Poppo instigated a war with Saxony in 882 and in 883 he and his brother Egino fought a civil war for control of Thuringia, in which the latter was victorious.
Sorbs arrived in the area extending between the Bober, Kwisa, and Oder rivers to the East and the Saale and Elbe rivers to the West during the sixth century A.D. In the North, the area of their settlement reached Berlin. The earliest surviving mention of the tribe was in 631 A.D., when Fredegar’s Chronicle described them as "Surbi" and as under the rule of a Dervan, an ally of Samo. The Annales Regni Francorum state that in 806 A.D. Sorbian Duke Miliduch fought against the Franks and was killed. In 840, Sorbian Duke Czimislav was killed. In 932, Henry I conquered Lusatia and Milsko. Gero II, Margrave of the Saxon Ostmark, reconquered Lusatia the following year and, in 939, murdered 30 Sorbian princes during a feast. As a result, there were many Sorbian uprisings against German rule. A reconstructed castle, at Raddusch in Lower Lusatia, is the sole physical remnant from this early period.
The Duchy of Franconia emerged from the partitioning of Austrasia in 817. By comparison to the Duchy of Bavaria, Franconia was mere collection of large estates controlled by counts. To describe it as colonial would not be too far from the truth as many areas still followed pagan practices.
One of the five Stem Duchies of East Francia, it stretched along the valley of the River Main from its confluence with the Upper Rhine up to the Bavarian March of the Nordgau, in the areas of the present-day Bavarian region of Franconia, the adjacent southern parts of the Free State of Thuringia, northern Baden-Württemberg (i.e. Rhine-Neckar and Heilbronn-Franken) and Hesse. It also included several Gaue on the left bank of the Rhine around the cities of Mainz, Speyer and Worms comprising present-day Rhenish Hesse and the Palatinate region.
Located in the centre of what was to become the German kingdom about 919, it bordered the stem Duchy of Saxony in the north, Austrasian Lorraine (Upper and Lower Lorraine) in the west, the Duchy of Swabia in the southwest and the Duchy of Bavaria in the southeast.
Unlike the other stem duchies, Franconia did not evolve into a stable political entity, though the local Salian counts held large estates in the western parts (Rhenish Franconia). In 906 the Conradine relative Count Conrad the Younger in the Lahngau is mentioned as a dux Franconiae. Upon the extinction of the East Frankish Carolingians in 911, he was elected the first German king (as Conrad I, Rex Francorum according to Salic law) and was succeeded as Franconian duke by his younger brother Eberhard. However, the Conradines did not prevail against the rising Saxon Ottonians:
(Compiled from various Wiki sources)
Next, the northern region of East Francia.