Saxony-Altenburg was a historical duchy located in central Germany. It existed from the early 19th century until 1918, when it became part of the Free State of Thuringia. The region is known for its picturesque landscapes, including forests and hills, and has a rich cultural heritage. The capital of Saxony-Altenburg was the city of Altenburg, which played a significant role in the duchy's administration and culture. The area is also recognized for its historical significance, including connections to the House of Wettin, a prominent royal family in German history.