 The black-white-red tricolour remained the flag of Germany until the end of the German Empire in 1918, in the final days of World War I.Following the declaration of the German republic in 1918 and the ensuing revolutionary period, the so-called Weimar Republic was founded in August 1919.To form a continuity between the anti-autocratic movement of the 19th century and the new democratic republic, the old black-red-gold tricolour was designated as the national German flag in the Weimar Constitution in 1919.