Peter III of Russia
From 1727 to 1750 Prince Adolf Frederick was the prince-bishop of Lübeck. This meant he ruled a fief around and including Eutin. After his first cousin, Charles Frederick, Duke of Holstein-Gottorp, died in 1739, Adolf Frederick became the administrator of Holstein-Kiel during the minority of the duke's orphan son, Charles Peter Ulrich. Shortly afterward, the young boy was invited to Russia by his maternal aunt, Empress Elizabeth, who soon declared him her heir. He later became known as Peter III of Russia.