| frederick i | (n) son of Frederick William who in 1701 became the first king of Prussia (1657-1713) |
| frederick i | (n) Holy Roman Emperor from 1152 to 1190; conceded supremacy to the pope; drowned leading the Third Crusade (1123-1190), Syn. Frederick Barbarossa, Barbarossa |
| frederick ii | (n) king of Prussia from 1740 to 1786; brought Prussia military prestige by winning the War of the Austrian Succession and the Seven Years' War (1712-1786), Syn. Frederick the Great |
| frederick ii | (n) the Holy Roman Emperor who led the Sixth Crusade and crowned himself king of Jerusalem (1194-1250), Syn. Holy Roman Emperor Frederick II |