Frederick I

noun
1.
("Frederick Barbarossa") 1123?–90, king of Germany 1152–90; king of Italy 1152–90: emperor of the Holy Roman Empire 1152–90.
2.
1194–1250, king of Sicily 1198–1212: as Frederick II, king of Germany and emperor of the Holy Roman Empire 1215–50.
3.
1657–1713, king of Prussia 1701–13 (son of Frederick William the Great Elector).
British Dictionary definitions for Frederick I

Frederick I

/ˈfrɛdrɪk/
noun
2.
1657–1713, first king of Prussia (1701–13); son of Frederick William