Henry the Lion from the Welf dynasty is one of the most powerful imperial sovereigns of the 12th century. He succeeded in continually expanding his territory through skilled politics and administration.
In 1147 he married Clementia of Zähringen (died around 1167), through whom he acquired sovereignty over Badenweiler Castle and the surrounding areas. Supposedly as the result of being too closely related, he divorced Clementia in 1162. The true motivations are probably based on the pressure which his cousin, Emperor Frederik I (Barbarossa), exerted on him. Barbarossa disliked the close ties between the Welf and the Zähringers, as it endangered his position of power. In addition, he also offered Henry the Lion possessions in the Harz Mountains in exchange for Badenweiler in order to enlarge his neighboring territories in Alsace. Henry agreed in order to secure his ancestral homeland in Saxony, primarily in the continuous conflict with the Ascanian Albert the Bear and his sons.
The daughter of Duke Philip the Bold from Burgundy and Margarete of Flanders married Duke Leopold IV of Austria in 1393. As a morning gift he brought the Upper Rhine (Haut-Rhin) region into the marriage. Katharina succeeded in obtaining far-reaching concessions and keeping her marriage estate in her own hands by having Leopold transfer the administration of the land to her. She located her seat of government in Alsace, near her homeland of Burgundy. The local royalty was indignant about being subjected to a woman who, in addition, also spoke a foreign language and brought in foreign traditions.
Following the separation of Katharina and Leopold in 1404, Katharina chose Badenweiler Castle as her residence, which was in the possession of the Duke as security at that time. Following Leopold's death in 1411, Katharina continued her reign, however had to provide her brothers-in-law with securities.
Hilda Charlotte Wilhelmine of Nassau, born on 5 November 1864 in Biebrich near Wiesbaden, married the Hereditary Grand Duke Friedrich (from 1907 as Friedrich II Grand Duke of Baden) on 20 September 1885, and was therefore the last Grand Duchess of Baden. Although the marriage of the two was politically motivated, it proved to be a happy, if childless, one. As the Grand Duchess tended to be considered a reserved and modest woman, she was also unable to prevail against her mother-in-law Luise. It is for this reason then that she continued to live in the palace of the Hereditary Grand Duke (today the Federal High Court) even after her husband took the throne and left the palace to the old Grand Duchess. Following her husband's death in 1928, she lived in Freiburg, Zwingenberg and Badenweiler. On 8 February 1952 she passed away in Badenweiler. After her death the palace was turned over to the community of Badenweiler.