Operation Margarethe was the occupation of Hungary by Nazi German forces during World War II, as it was ordered by Hitler on 12 March 1944. A plan for the occupation of Romania was devised under the name Operation Margarethe II but was never carried out.
Hungarian Prime Minister Miklós Kállay (in office from 1942), with the knowledge and approval of Regent Miklós Horthy, secretly sought to negotiate a separate peace with the Allies in early 1944. German dictator Adolf Hitler wanted to prevent the Hungarians from turning against Germany. Hitler desperately needed Hungary's oil. On 12 March 1944, he ordered German troops to capture critical Hungarian facilities.
Hitler invited Horthy to the palace of Klessheim, outside of Salzburg in Austria, on 15 March. While the two heads of state conducted their negotiations, German forces quietly moved into Hungary. The meeting served merely as a German ruse to keep Horthy out of the country and to leave the Hungarian Army without orders. Negotiations between Horthy and Hitler lasted until the 18th, when Horthy boarded a train to return home.
When he arrived in Budapest, it was German soldiers who greeted him. Horthy was told[by whom?] that Hungary could only remain sovereign if he removed Kállay in favour of a government that would cooperate fully with the Germans. Otherwise, Hungary would be subject to undisguised occupation. Horthy appointed Döme Sztójay as prime minister to appease German concerns. The occupation was a complete surprise, which resulted in it being quick and bloodless. The initial plan was to immobilise the Hungarian army, but with Soviet forces advancing from the north and east, and with the prospect of British and American forces invading the Balkans, the German military decided to retain Hungarian forces in the field, sending a portion to defend the passes through the Carpathians against possible invasion.
As a consequence of the Nazi occupation, Adolf Eichmann arranged the transportation of 550,000 Hungarian Jews from wartime Hungary (including Jews from territories annexed from Czechoslovakia, Romania, and Yugoslavia) to the Nazi death camps, with the collaboration of Hungarian authorities.[need quotation to verify]
Operation Margarethe II was the name for a planned Nazi German invasion of Romania by German forces in conjunction with those of Hungary should the Romanian government decide to surrender to the Soviet Union and switch sides. Romania did in fact surrender in August 1944 (after King Michael's Coup), but this operation was never implemented.