"MIL:BRIEF.ST.LUXEM=BURG" in black on lettersheet, franked with Luxemburg 1865/75, 25 c. blue, tied by cds. "LUXEMBOURG 24 AOUT 67" to Sobernheim with railway transit mark and arrival mark of the next day; some light folds, not affecting the stamp; a most remarkable and unique cover of the last day of the Prussian post office at the fortress with extremely scarce usage of the rouletted 25 c.
Provenance: Illustrated at C. Brühl (fig. 32)
