'Stettin' was the German occupation of Memel (now Klaipėda) (22/23 March 1939).
The German ultimatum to Lithuania was presented orally to Juozas Urbsys, the Lithuanian foreign minister, by Joachim Ribbentrop, the German foreign minister, on 20 March 1939 and demanded that Lithuania concede the Klaipėda region (the Memel territory), which had been detached from Germany after World War I, failing which German forces would attack Lithuania. After years of increasing tension between Lithuania and Germany, the steady escalation pro-German propaganda in the region, and continued German expansion, the demand was expected by the Lithuanians.
The ultimatum was issued just five days after the German occupation of the rump of Czechoslovakia left after the loss of the Sudetenland in the Munich agreement of September 1938, and the four signatories of the 1924 Klaipėda Convention, which had guaranteed the protection of the status quo in the region, did not offer any material assistance. The UK and France were still following their policy of appeasement, and Italy and Japan openly supported Germany. Lithuania had little alternative but to accept the ultimatum on March 22. This was Germany’s final territorial acquisition before World War II.
Even before the signature of the treaty, German soldiers had started to land at Memel watched from the pocket battleship Deutschland by Adolf Hitler, who then toured the city and gave a short speech.
Apart from Deutschland, the German naval force involved in 'Stettin' included the pocket battleship Admiral Graf Spee, the light cruisers Nürnberg, Leipzig and Köln, two squadrons of destroyer, three flotillas of torpedo boats, and one flotilla of tenders. At the time the Lithuanian navy comprised just one warship, the 500-ton Prezidentas Smetona, a converted minesweeper.
Even as the Germans were celebrating the return of the city, European politicians expressed fears that the Free City of Danzig would be the next target for Hitler’s expansionist ambitions.