In the first months of World War II, Romania was officially neutral. However the Molotov–Ribbentrop Pact of 23 August 1939, initially a secret document, stipulated, among other things, Soviet "interest" in Bessarabia. After the invasion of Poland by Nazi Germany on 1 September, joined by the Soviet Union on 17 September, Romania granted refuge to members of Poland's fleeing government and military. Even after the assassination of Călinescu on 21 September, King Carol tried to maintain neutrality, but the later surrender by France and Britain's retreat from Europe rendered them unable to fulfil their assurances to Romania. A lean toward the Axis powers was probably inevitable.