A real philatelic treat. The first Polish stamp affixed to the envelope of Leopold Kronenberg of Warsaw, with the attestation of the Expert of the Polish Philatelic Union, Lesław Schmutz, issued on November 6, 2012: "The letter from Warsaw to St. Petersburg mailed on May 15, 1862, paid for with the first Polish stamp issued on January 1, 1860, shown in the photograph pasted to the attestation...