c.1880s German Empire folded letter Berlin – Halle / Jena with 10 Pfennig stamp and Kösen advertising seal

Original 19th‑century folded letter from the German Empire on grey grid paper. The front carries a red 10 Pfennig “Deutsches Reich / Reichspost” stamp cancelled with boxed Berlin / Halle markings, and is addressed in old German handwriting. On the reverse there is a circular Jena date stamp and a re