Knights of the Empire
In South Germany and Rhineland. Acknowledged no overlordship. If count these, there were 2,000 German states (more than the '300' usually referred to). They were private persons enjoying sovereign status - last anomaly of neofeudalism and they protected their freedoms jealously - they were sticklers for "German Liberties"
Electors of HRE
By Golden Bull, 1356, there were to be 7 electors of HRE- 3 ecclesiastical/church officials (Cologne, Trier, Mainz) + Palatine, Saxony, Brandenberg & Bohemia. Added 2 more by 1700 - Bavaria(Wittelsbach family) and Hanover(Guelph family). Nearly half of the electors were Protestant.
IUS EUNDI PARTES
Right of sitting apart.....on issues of religion in the imperial diet -> argument over calendar - i.e. when to have Easter. Led to much delay & effectiveness was very difficult in the imperial diet.
Perpetual Diet of Regensburg
From 1663-1806. Met to consider how to respond to the Turk advance on R. Danube - ineffectual and unresponsive to events and issues. Last Diet to be convoked - lasted forever (i.e. never officially dismissed) and achieved virtually nothing.
Family of electors of House of Brandenburg (centered around what is now Berlin) - inherited bits of territory from Rhine to Vistula - eventually became Prussia.
Aristocratic House of Austria - an archduchy on upper River Danube. Habsburgs also became hereditary Kings of Bohemia after Treaty of Westphalia.