Situation after the conquest in the late 13th century. Areas in purple under control of the Monastic State of the Teutonic Knights

As a result of the peace negotiations, the states south of the Main remained theoretically independent, but received the (compulsory) protection of Prussia. Additionally, mutual defence treaties were concluded. However, the existence of these treaties was kept secret until Bismarck made them public in 1867 when France tried to acquire Luxembourg.

The two decades after the unification of Germany were the peak of Prussia's fortunes, but the seeds for potential strife were built into the Prusso-German political system.

Frederick III became emperor in March 1888, after the death of his father, but he died of cancer only 99 days later.

This centralising policy went even further in Prussia. From 1934 to 1945, almost all ministries were merged and only a few departments were able to maintain their independence. Hitler himself became formally the governor of Prussia. However, his functions were exercised by Hermann Göring as Prussian prime minister.

Prussia contained a relatively large Jewish community, which was mostly concentrated in large urban areas. According to the 1880 census, it was the biggest one in Germany with 363,790 individuals.