Prussia

The grand arms (Großes Wappen) of Prussia around 1873

Prussia (German: Preußen) refers to several related areas in Europe, primarily as a German territory. Prussia was formally abolished (German: Abschaffung von Preußen) by a decree of the occupying WWII Allied Control Council on 25th February 1947.

Territories

Royal Standard of the King of Prussia (1871–1918)

The undefined/borderless homeland of the ancient Prussians, a non-Slav Baltic peoples, which was conquered by crusade by the German Teutonic Knights. Thereafter it became the theocratic state, with recognized borders, of the Teutonic Order on the southeastern coast of the Baltic Sea.

In 1525, it became a secularized "Duchy of Prussia" within the Holy Roman Empire of the German Nation under Grand Master Albert of Brandenburg-Ansbach, a member of a cadet branch of the Hohenzollerns, and his successors. Prince-elector John Sigismund, Elector of Brandenburg, inherited the Duchy of Prussia in 1618, thus uniting Brandenburg and Prussia under one ruler in a personal union; the Elector's state became known as Brandenburg-Prussia.

The "Kingdom of Prussia", as it became from January 1701, continued its rule by the German Hohenzollern dynasty, including the former Duchy of Prussia and Electorate of Brandenburg, with Berlin as its capital. Initially a part of the Holy Roman Empire, Prussia gradually expanded in size, eventually becoming the dominant part of the German Empire, with the Prussian King also being the German Emperor.

As "Free State of Prussia" part of the Weimar Republic and National Socialist Germany.

Colours

The colors black and white as the national colors of Prussia and the black eagle as a heraldic animal go back to the Teutonic Order in the 13th century. The knights of the order wore a white shield with a black cross. The significant Grand Master of the Teutonic Order Hermann von Salza received the black imperial eagle (Reichsadler) as a sign of grace from Roman-German Emperor Friedrich II on the occasion of his appointment as imperial prince in the Golden Bull of Rimini and carried it on a white shield. The Hohenzollern dynasty, which appeared in the 17th century as the rulers of Mark Brandenburg and the Duchy of Prussia, under which the two countries grew together to form a unified Prussian state, already had a shield “through white and black quartered” as a family crest in medieval times. The flag of the Kingdom of Prussia commemorates the coronation of Frederick III. of Brandenburg in 1701, when the "Duchy of Prussia" became the "Kingdom of Prussia". On the kingdom's flag, the Prussian eagle now bore royal insignia instead of ducal ones. It became the flag of the Brandenburg-Prussian state, a monarchy that had been called "Prussia" since about the mid-18th century.

Their colors, black and white, were one of the origins, together with the white and red of the Hanseatic League, for the black, white, and red flag of the German Empire.