Stamp in honour of the 50th anniversary of the formation of the Spartacus League, German Democratic Republic -- Daily LIFT #732
In June of 1916, Rosa Luxemburg and Karl Liebknecht were imprisoned by the Imperial German authorities for their steadfast opposition to World War I.
They had split from the Social Democratic Party, which capitulated to nationalism and backed the war and the German war effort, and they had formed the Spartacus League in January of 1916.
50 years later the German Democratic Republic released a stamp set to commemorate them and their bravery.