Prussia

PRUSSIA

Dukes of Prussia
1525–1568: Albrecht I
1568–1618: Albrecht II Friedrich co-inheritor (son of)
1568–1571: Joachim I/II Hector co-inheritor (also Elector of Brandenburg) 1578–1603: Georg Friedrich I/I/I/I (Regent, also Margrave of Brandenburg-Ansbach, Margrave of Brandenburg-Kulmbach and Duke of Brandenburg-Jägerndorf)
1603–1608: Joachim I/I/III Friedrich (Regent, also Duke of Brandenburg-Jägerndorf and Elector of Brandenburg)
1608–1618: Johann I/III Sigismund (Regent, also Elector of Brandenburg) 1618–1619: Johann I/III Sigismund (Regent, also Elector of Brandenburg)
1619–1640: Georg Wilhelm I/I (son of, also Elector of Brandenburg)
1640–1688: Friedrich I/III Wilhelm the Great (son of, also Elector of Brandenburg)
1688–1701: Friedrich II/IV/I (also Elector of Brandenburg and King in Prussia)

Kings in Prussia
1701–1713: Friedrich I/II/IV (also Duke of Prussia and Elector of Brandenburg)
1713–1740: Friedrich Wilhelm I (son of)
1740–1786: Friedrich II the Great (son of, later also King of Prussia)

Kings of Prussia
Friedrich II the Great (1740–1786) (son of, before King in Prussia)
Friedrich Wilhelm II (1786–1797) (nephew of)
Friedrich Wilhelm III (1797–1840) (son of)
Friedrich Wilhelm IV (1840–1861) (son of)
Wilhelm I (1861–1888) (brother of)
Friedrich III (1888) (son of)
Wilhelm II (1888–1918) (son of)

German Kings & Emperors
1871–1888: Wilhelm I (also King of Prussia)
1888: Friedrich III (son of, also King of Prussia)
1888–1918: Wilhelm II (grandson of, also King of Prussia)

References
The Hohenzollerns in Brandenburg
Prussia: Chronicle of the German States
Prussia's Gallery of Kings