Attempts at creation of a federation remained unsuccessful and the German Confederation collapsed in 1866 when war ensued between its two most powerful member states, Prussia and Austria.
The North German Confederation which lasted from 1867–1871, created a closer union between the Prussian-aligned states while Austria and most of Southern Germany remained independent.
Legally, no kingdoms could exist in the Holy Roman Empire except for Bohemia.
However, Frederick took the line that since Prussia had never been part of the empire and the Hohenzollerns were fully sovereign over it, he could elevate Prussia to a kingdom.
The Kingdom of Prussia was devastated from the Thirty Years' War and poor in natural resources.
Its territory was disjointed, stretching 1,200 km (750 mi) from the lands of the Duchy of Prussia on the south-east coast of the Baltic Sea to the Hohenzollern heartland of Brandenburg, with the exclaves of Cleves, Mark and Ravensberg in the Rhineland.
However, by this time the emperor's authority was only nominal.
The rulers of the empire's various territories acted largely as the rulers of sovereign states, and only acknowledged the emperor's suzerainty in a formal way.
While the personal union between Brandenburg and Prussia legally continued until the end of the empire in 1806, from 1701 onward Brandenburg was de facto treated as an integral part of the kingdom.
These issues led to feuds, wars, trade competition and invasions.