153 Years Ago

The envelope also featured a photo that replicated the scene of a civil war battle and had words “The War for the Union,” written on it. The actual postage stamp was torn off but it did not take much time to Boes to realize that it was sent 153 years earlier. Surprisingly, the letter reached the post office in April of 2015. Where was it during all these years? And with what purpose was it sent to the Postmaster? And most importantly who had written this letter?