Wait a minute, I'm confused. Weren't Prussia and Brandenburg the same country? Why do they hate each other?
“As I can assure you, they hardly hate one another - they are brothers nowadays.”
[1785 HRE takeover]
[The Duchy of Prussia was the successor of the state of the Teutonic Knights, and as such was not part of the Holy Roman Empire. When the Margraviate Brandenburg sought to expand its territory and influence, it managed to connect itself to Prussia (and some regions in the Rhineland) through a personal union - the result of a marriage between the margraviate’s son and the daughter of the duke of Prussia. However, the territories were not connected by land and otherwise continued to exist by themselves.
After the 30 Years’ War, Friedrich I. (the Great Elector) reformed his lands which had been ravaged by the war during the rule of his father, and created the kingdom of Prussia in 1701. He was thereby taking advantage of the fact that the duchy of Prussia was not part of the Holy Roman Empire, as the only kingdom allowed within the borders of the empire was Bohemia.
Despite being one of the seven electors of the emperor, Brandenburg was quite poor, as was Prussia. Both regions suffered from very poor soil - in Brandenburg the ground was very sandy, while Prussia’s earth was too muddy for great agricultural efforts. The kingdom was a target of ridicule across Europe even as it rose to prominence due to the fact that its territories were scattered across the lands.]