Sweden. Foreign-related cover. Finland. Fantastic unpaid letter dated "Stockholm 6 Nov. 1854" sent to Helsinki. On account of the first naval blockade during the Crimean War, the letter was posted on board the steamer 'NAGLER' in Stockholm and sent via Kalmar to STETTIN 9.11. The letter was then conveyed via Riga and St. Petersburg to Helsinki. Cancel AUS SCHWEDEN. Postage due "37" (kop) noted on reverse. One of only a very few known letters sent southbound during the first blockade. International exhibition item in EXCELLENT quailty.