Context: Because the duchy was outside of the core Holy Roman Empire, the prince-electors of Brandenburg were able to proclaim themselves King of Prussia beginning in 1701. After the annexation of most of western Royal Prussia in the First Partition of the Polish-Lithuanian Commonwealth in 1772, eastern (ducal) Prussia was connected by land with the rest of the Prussian state and was reorganized as a province the following year (1773). Between 1829 and 1878, the Province of East Prussia was joined with West Prussia to form the Province of Prussia.

Question: Why were the prince electors able to proclaim themselves King of Prussia?
Answer: Because the duchy was outside of the core Holy Roman Empire

Question: In what year were the prince electors elect them selves as King?
Answer: 1701

Question: What time period did East Prussia and West Prussia join to become Prussia?
Answer: Prussia

Question: In what year was the Holy Roman Empire founded?
Answer: Unanswerable

Question: What type of government entity was Prussia prior to 1773?
Answer: Unanswerable

Question: How could those in eastern Prussia get to the rest of the Prussian State prior to 1772?
Answer: Unanswerable

Question: How was the Holy Roman Empire connected to Brandenburg?
Answer: Unanswerable