The region on the Pleiße River was part of a huge forest, where the Thuringii formed the Thuringian Kingdom. After this was in 531 taken over by the Franks, Slavic people were also moving in. Thuringians reestablished independent rule. The castle of Altenburg already existed in the 10th century, it became an imperial seat. In the following centuries German settlers from other parts moved in. It was part of the Margravate of Meissen in the 14th century. At this time most of the forests were cleared.