Background
Eleanor Charlotte was the younger of two daughters of Duke Francis Henry of Saxe-Lauenburg (1604–1658), who held Franzhagen as an appanage, from his marriage to Marie Juliane (1612–1665), daughter of John VII, Count of Nassau-Siegen.
Eleanor Charlotte was the younger of two daughters of Duke Francis Henry of Saxe-Lauenburg (1604–1658), who held Franzhagen as an appanage, from his marriage to Marie Juliane (1612–1665), daughter of John VII, Count of Nassau-Siegen.
In 1667 Christian Adolph and his hereditary estates went bankrupt, and King Frederick III of Denmark as the liege lord retracted the fief. Eleanor Charlotte traveled to Copenhagen, and negotiated personally but unsuccessfully with the king for the return of the territories. Her spouse received an annual stipend, which helped the couple to fund a princely lifestyle.
After George William, Duke of Brunswick and Lunenburg, Prince of Celle, had successfully conquered and annexed Saxe-Lauenburg proper, Eleonore Charlotte continued to pursue her succession in the Saxe-Lauenburgian exclave of the Land of Hadeln, which, however, came under imperial stewardship.
However, under Salic law, women were not allowed to inherit. The couple moved to Franzhagen Castle in the Duchy of Saxe-Lauenburg, which Eleonore Charlotte had inherited, thereby founding the Schleswig-Holstein-Sonderburg-Franzhagen line.