Lot 91105 – 1852-58, 1kr black on olive-grey, a very fresh mint block of four

1852-58, 1kr black on olive-grey, a very fresh mint block of four with original gum, just touched in part of the left side, otherwise clear to very large margins showing parts of adjoining stamps at base, two stamps with very light crease, otherwise a very fine and rare multiple; cert. Helbig (2000), (Michel €1’800); ex « Pour le Mérite » collection.