Crown of Frederick I of Prussia
The Crown of Frederick I (German: Krone von Friedrich I.) was made by the Court Jewellers for Frederick I of Prussia in 1701, who crowned himself and his wife Sophie Charlotte in a baroque ceremony at Königsberg Castle, Königsberg. The crown was also used for the coronation of Frederick William I and his son, Frederick II (better known as Frederick the Great).
Source: Wikipedia — Crown of Frederick I of Prussia (CC BY-SA 4.0)