The Prussian war flag (3:5), adopted November 28, 1816, was originally swallow-tailed for one-fifth of the total length; the tail was later abandoned. At two fifths it showed the Prussian eagle (two-thirds of the flag's height). In the canton, the Iron Cross was placed (one-third of the flag's height).

The Iron Cross was established in 1813 during the war against Napoleon I as a decoration for courageous common soldiers. It was renewed in the Franco-Prussian War of 1870 and in World War I. It also appeared in the canton of the war flag of the German Empire.

The royal standard of Prussia showed the Iron Cross charged with the shield and crown of the small state arms surrounded by the collar of the Order of the Black Eagle. On the blades of the cross is the motto Gott mit uns. Between the arms were Prussian eagles along the edges and a royal crown in carré with them, all on a purple or red background.

After the German Revolution of 1918–19, the Prussian state was slow to adapt its heraldry to republican forms. Only July 11, 1921, new arms were decreed by the Prussian prime minister. The 'gothic' eagle made way for the more natural-looking flying one and lost all its garments.

On December 16, 1921, the Ministry of State decreed that the Prussian flag was to be only black and white.

On February 24 and April 23, 1922, the ministry issued a service flag similar to the national flag of the 19th century – black borders above and below, being one-sixth of the total height of the flag, with the new eagle.

The Germany national football team home dress has always been a white jersey and black shorts, the colours of the Prussian flag.