The Duke of Saxe-Altenburg was a noble title in the German region of Saxe-Altenburg, which was part of the larger Saxony area. The duchy was established in the early 19th century and was one of the smaller principalities within the German Confederation. The dukes ruled over the region until the end of the monarchy in Germany after World War I. The last reigning duke was Ernst II, who ruled from 1908 until 1918. Following the abdication of the monarchy, the title became largely ceremonial, and the family lost its political power. Today, the descendants of the dukes still exist, but they no longer hold any official status.