Hungary–Romania relations
During World War II, Hungary and Romania became allies and participated in the war against the Soviet Union. But after the coup on 23 August 1944 Romania switched sides and fought against Hungary. Consequently, Soviet and Romanian troops invaded Hungary, occupied Northern Transylvania by October 1944 and re-established the Romanian administration in the region in March 1945. The 1947 Treaty of Paris reaffirmed the borders between Romania and Hungary as originally defined in Treaty of Trianon 27 years earlier, thus confirming the return of Northern Transylvania to Romania.
Ion Antonescu
In June of that year, Romania joined the attack on the Soviet Union, led by Germany in coalition with Hungary, Finland, the State of Slovakia, the Kingdom of Italy and the Independent State of Croatia. Antonescu had been made aware of the plan by German envoys, and supported it enthusiastically even before Hitler extended Romania an offer to participate. On 18 June 1941, Antonescu gave orders to his generals about "cleansing the ground" of Jews when Romanian forces entered Bessarabia and Bukovina. Right from the start, Antonescu proclaimed the war against the Soviet Union to be a "holy war", a "crusade" in the name of Eastern Orthodox faith and the Romanian race against the forces of "Judo-Bolshevism". The propaganda of the Antonescu regime demonized everything Jewish as Antonescu believed that Communism was invented by the Jews, and all of the Soviet leaders were really Jews. Reflecting Antonescu's anti-Slavic feelings, despite the fact that the war was billed as a "crusade" in defense of Orthodoxy against "Judeo-Bolshevism", the war was not presented as a struggle to liberate the Orthodox Russians and Ukrainians from Communism; instead rule by "Judeo-Bolshevism" was portrayed as something brought about the innate moral inferiority of the Slavs, who thus needed to be ruled by the Germans and the Romanians. The Romanian force engaged formed a "General Antonescu Army Group" under the effective command of German general Eugen Ritter von Schobert. Romania's campaign on the Eastern Front began without a formal declaration of war, and was consecrated by Antonescu's statement: "Soldiers, I order you, cross the Prut River" (in reference to the Bessarabian border between Romania and post-1940 Soviet territory). A few days after this, a large-scale pogrom was carried out in Iași with Antonescu's agreement; thousands of Jews were killed in the bloody Iași pogrom. Antonescu had followed a generation of younger right-wing Romanian intellectuals led by Corneliu Zelea Codreanu who in the 1920s-30s had rejected the traditional Francophila of the Romanian elites and their adherence to Western notions of universal democratic values and human rights. Antonescu made it clear that his regime rejected the moral principles of the "demo-liberal world" and he saw the war as an ideological struggle between his spiritually pure "national-totalitarian regime" vs. "Jewish morality". Antonescu believed that the liberal humanist-democratic-capitalist values of the West and Communism were both invented by the Jews to destroy Romania. In a lengthy speech just before the war, Antonescu attacked democracy in the most violent terms as it allowed Jews equal rights and thus to undercut the Romanian "national idea". As such, Antonescu stated what was needed was a "new man" who would be "tough", "virile" and willing to fight for an ethnically and religiously "pure" Romania. Despite his quarrel with Sima, much of Antonescu's speech clearly reflected the influence of the ideas of the Iron Guard that Antonescu had absorbed in the 1930s. Antonescu's anti-Semitism and sexism went so far that he tacitly condoned the rape of Jewish women and girls in Bessarabia and northern Bukovinia by his forces under the grounds that he was going take away all of the property that the Jews had "stolen" from the Romanians, and as far he was concerned, Jewish females were just another piece of property. Since the Jewish women were going to exterminated anyway, Antonescu felt there was nothing wrong about letting his soldiers and gendarmes have "some fun" before shooting them.
After becoming the first Romanian to be granted the Knight's Cross of the Iron Cross, which he received from Hitler at their August 6 meeting in the Ukrainian city of Berdychiv, Ion Antonescu was promoted to Marshal of Romania by royal decree on August 22, in recognition for his role in restoring the eastern frontiers of Greater Romania. In a report to Berlin, a German diplomat wrote that Marshal Antonescu had syphilis and that "among [Romanian] cavalry officers this disease is as widespread as a common cold is among German officers. The Marshal suffers from severe attacks of it every several months." Antonescu took one of his most debated decisions when, with Bessarabia's conquest almost complete, he committed Romania to Hitler's war effort beyond the Dniester—that is, beyond territory that had been part of Romania between the wars—and thrust deeper into Soviet territory, thus waging a war of aggression. On August 30, Romania occupied a territory it deemed "Transnistria", formerly a part of the Ukrainian SSR (including the entire Moldavian ASSR and further territories). Like the decision to continue the war beyond Bessarabia, this earned Antonescu much criticism from the semi-clandestine PNL and PNȚ. Insofar as the war against the Soviet Union was a war to recover Bessarabia and northern Bukovina-both regions that been a part of Romania until June 1940 and that had Romanian majorities-the conflict had been very popular with the Romanian public opinion. But the idea of conquering Transnistria was not as that region had never been part of Romania, and a minority of the people were ethnic Romanian. Soon after the takeover, the area was assigned to a civil administration apparatus headed by Gheorghe Alexianu and became the site for the main component of the Holocaust in Romania: a mass deportation of the Bessarabian and Ukrainian Jews, followed later by transports of Romani Romanians and Jews from Moldavia proper (that is, the portions of Moldavia west of the Prut).