Brief details of these two important German dynasties have appeared before on in General-History.com. Here are some additional notes:
The Hohenstaufen royal dynasty got its name from the castle of Staufen, in north Swabia. From 1138 to 1254 members of the family wore the crown as Holy Roman Emperor (q.v.). The dynasty reached its most significant period with Frederick I Barbarossa and Frederick II; both were Kings of Germany and Sicily. The dynasty is best remembered for its support of culture and courtly behaviour, though their wars are by no means to be discounted.
As Holy Roman Emperor:
1138 – 1152 Conrad III
1152 – 1190 Frederick I Barbarossa
1190 – 1107 Henry VI
1198 – 1208 Philip of Swabia
1198 – 1214 Otto IV (both Otto and Philip maintained their claim)
1215 – 1250 Frederick II
1250 – 1254 Conrad IV
The German dynasty of Hohenzollern ruled Brandenburg/Prussia from 1415 to 1918, and Imperial Germany from 1871 to the end of the Great War. The family was first noted in the ninth century, in Swabia, and a branch became Burgraves of Nuremberg. Then a descendant, Frederick VIII was awarded the title of Elector of Brandenburg in the same year as the Battle of Agincourt (1415). The Thirty Years War over, the family continued its policy of expansion and consolidation of power, starting a lengthy rivalry with the House of Habsburg (1740 – 1871). Otto von Bismarck ensured that the Hohenzollerns obtained the imperial title in 1871, but the Great War destroyed Hohenzollern fortunes and forced abdication on the last emperor, Wilhelm II, a grandson of Queen Victoria of Britain.
As Electors of Brandenburg:
Frederick I (1417 – 1440), Frederick II, Albert, John, Joaquim I, Joaquim II, John George, Joaquim Frederick, John Sigismund, George, Frederick William (the Great Elector, 1640 – 1688).
As Kings of Prussia:
Frederick I (Frederick III as Elector Brandenburg 1688 – 1713), Frederick William I, Frederick II The Great, Frederick William II, Frederick William III, Frederick William IV (1840 – 1861).
As Emperors of Germany:
William I (also King of Prussia) 1861 – 1868, Frederick III (only 1888), Wilhelm (William) II 1888 – 1918