Unissued stamp from 2015 supposed to show Mr. Luka Sorkočević, Ragusan 18th ct. composer. Three stamps were envisaged for the set 'Famous Croats' in 2015 featuring Messrs. Luka Sorkočević, J.J. Strossmayer and Ivan Supek. By mistake the image of American president Thomas Jefferson was placed on the Kn. 3.10 stamp. This error was noted just before the release of the set and the entire run of the Kn. 3.10 stamp was withdrawn and destroyed. It is though known that one post office sold 22 examples prior to the release date. In view of the events and given the fact that - insofar as known - not a single copy has reached philatelic market to date, we consider this stamp could become the ‘Croatian Mauritius’. As this error is also important for the American philatelic market we believe the price will only increase in the future.