 In 1921, the Republic of Panama planned to issue a Centennial commemorative series in honor of the 100th anniversary of Panama's independence from Spain.The Canal Zone was invited to participate in a postal way and the Canal Zone's Executive Secretary was pleased to accept their invitation.By the middle of January 1924, all the stamps of the 1¢ and 2¢ denominations were nearly exhaustedwhich prompted the next production of stamps, issued that year.