Baden - 1851 Baden 9k Green Error

The Baden color error, 9 kreuzer Black on Green, was issued by the German Empire State in 1851. Since its discovery in 1894, 43 years later, the Baden error has only been up for auction a total of four times. There are only four known examples of the color error, three are cancelled, and only one is in mint condtion. This mint example first sold at a Berlin auction in 1919. In 1997, it again sold for the sum of $603,750.