Posted 5 years ago
DeutschOsterreich stamp. Deutsche is Germany, Osterreich is Austria. This is from after World War 1 when Germany and Austria combined. The Allies didn't like that.
It appears that a collector had bought it, never used it, and merely put a little tape on the back to hold it in his stamp-book. This is a little less common than its red counterpart from what I can tell, but the stamps from this time came in many variants.