interned the fleeing Polish government after its members had crossed the Polish–Romanian border on 17 September, forcing them to relegate their authority to what became the Polish government-in-exile. After the assassination of Prime Minister Armand Călinescu on 21 September King Carol II tried to maintain neutrality for several months longer, but the surrender of the Third French Republic and the retreat of British forces from continental Europe rendered the assurances that both countries had made to Romania meaningless. In 1940 Romania's territorial gains made following World War I were largely undone. In July, after a Soviet ultimatum, Romania agreed to give up Bessarabia and northern Bukovina (the Soviets also annexed the city of Hertsa, which was not stated in the ultimatum). Two-thirds of Bessarabia were combined with a small part of the Soviet Union to form the Moldavian Soviet Socialist Republic. The rest (northern Bukovina, the northern half of Hotin county and Budjak) was apportioned to the Ukrainian Soviet Socialist Republic. Shortly thereafter, on 30 August, under the Second Vienna Award, Germany and Italy mediated a compromise between Romania and the Kingdom of Hungary: Hungary received a region referred to as 'Northern Transylvania', while 'Southern Transylvania' remained part of Romania. Hungary had lost Transylvania after World War I in the Treaty of Trianon. On 7 September, under the Treaty of Craiova, Southern Dobruja (which Bulgaria had lost after the Romanian invasion during the Second Balkan War in 1913), was ceded to Bulgaria under pressure from Germany. Despite the relatively recent acquisition of these territories, they were inhabited by a majority of Romanian speaking people (except Southern Dobruja), so the Romanians had seen them as historically belonging to Romania, and the fact that so much land was lost without a fight shattered the underpinnings of King Carol's power. On 4 July, Ion Gigurtu formed the first Romanian government to include an Iron Guardist minister, Horia Sima. Sima was a particularly virulent antisemite who had become the nominal leader of the movement after the death of Corneliu Codreanu. He was one of the few prominent far-right leaders to survive the bloody infighting and government suppression of the preceding years. In the immediate wake of the loss of Northern Transylvania, on 4 September the Iron Guard (led by Horia Sima) and General (later Marshal) Ion Antonescu united to form the "National Legionary State", which forced the abdication of Carol II in favor of