3-5/8x6" signed envelope for the 1939 centennial of baseball. Postmarked Cooperstown, N.Y., June 12, 1939. "Base Ball Centennial 1839-1939 Commemorating 100 Years Of Baseball Invented By Col. Abner Doubleday At Cooperstown, New York In 1839." This text is interspersed w/ball player on large baseball bkg. and silhouettes of ball players underneath. 3¢ stamp features purpletone scene of children playing baseball. Wagner has signed "J. Honus Wagner June 27, 1939" above mailing address. The "Flying Dutchman" was one of the Hall of Fame's five original inductees in 1936 and played for the Louisville Colonels and Pittsburgh Pirates. (Ty Cobb, Walter Johnson, Christy Mathewson were also inducted into Hall of Fame in 1936.) Envelope has some lt. wear and aging along glued back panels which has come through faintly on front. Top of reverse flap has name and address stamp of recipient. Near-VF.