The Prussian monarchy refers to the royal family that ruled the Kingdom of Prussia from the late 16th century until the early 20th century. It began with the Hohenzollern dynasty, which played a significant role in the unification of Germany. The monarchy was characterized by a strong military tradition and a centralized government. The monarchy reached its peak under King Frederick II, also known as Frederick the Great, who expanded Prussia's territory and influence in Europe. The monarchy ended with the abdication of Kaiser Wilhelm II in 1918, following Germany's defeat in World War I, leading to the establishment of the Weimar Republic.