c.1870s German 1 Groschen postal stationery cover Rethem – Hannover

Original 19th‑century German postal stationery envelope with red 1 Groschen imprinted stamp (“DEUTSCHER POSTBEZIRK – EIN GROSCHEN POST‑COUVERT”), used from Rethem to Hannover. The indicium is cancelled by a clear circular RETHEM datestamp dated 26 June, and the address is written in attractive viole