Karl, Hereditary Prince of Mecklenburg-Güstrow

He was a son of Gustavus Adolph and his wife Magdalene Sibylle née Duchess of Schleswig-Holstein-Gottorp, a daughter of Frederick III.

Charles married on 10 August 1687 in Potsdam to Marie Amalie of Brandenburg, the daughter of the "Great Elector" Frederick William of Brandenburg.

He was the last surviving son of his father, and his wife lost her child when she learned of his fate, so that the Mecklenburg-Güstrow line died out when his father died in 1695.

His brother-in-law, Duke Adolf Frederick II of Mecklenburg-Strelitz claimed Mecklenburg-Güstrow.

However Duke Frederick William of Mecklenburg-Schwerin disagreed and the legal situation was unclear, leading to a long succession dispute.