[2] Mihailov was a Bulgarophile right-wing politician and former leader of the Internal Macedonian Revolutionary Organization (IMRO) who had been engaged in terrorist activity in Yugoslav and Greek Macedonia.
In January 1944 he had successfully lobbied the Germans to arm some Ohrana supporters and have them placed under Schutzstaffel (SS) command in Greek Macedonia, which had also been in part annexed by Bulgaria in 1941.
[5] During the last phase of the Second World War he tried to realise his plan with German political collaboration; however, he abandoned the implementation of this idea due to the lack of real military support.
Without the means to make the state a reality, this pretence dissolved as soon as the Yugoslav Partisans asserted their control following the withdrawal of German troops from the area by mid-November.
On 20 April, the Bulgarian army entered Greece and Yugoslavia with the aim of gaining access to the Aegean Sea in Thrace and eastern Macedonia.
[15][16] According to the Bulgarian historian Dobrin Michev, Mihailov, who lived in Zagreb during the war, traveled in disguise to Germany around 1 August 1943, where in the Führer Headquarters and in the premises of the Reich Security Main Office, he met with Hitler, Heinrich Himmler and other senior German officials, with whom, according to scant information, it was agreed that he would raise two or three volunteer battalions, armed with German arms and ammunition, to operate under the operational command and disposition of Reichsführer-SS Himmler.
According to Michev, at the same time, talks were also held in Sofia between high-ranking Schutzstaffel officials and the members of the Central Committee of IMRO Vladimir Kurtev, Zhoro Nastev and Dimitar Tsilev.
In an attempt to bring him under its control, Bulgaria lifted his death sentence and offered him to return to the country and take up a leading position in Vardar Macedonia, but he rejected this proposal.
On this basis, the Yugoslav communists, who supported the recognition of a separate Macedonian nation, managed to organize an earnest armed resistance against the Bulgarian forces in the autumn of 1943.
[23][24] On 23 August, Romania left the Axis Powers, declared war on Germany, and allowed Soviet forces to cross its territory to reach Bulgaria.
At that time, Bulgaria made a drive to find separate peace, repudiating any alliance with Nazi Germany, and declared neutrality on 26 August.
However, its secret negotiations with the Allies in Cairo, to allow it to retain the annexed areas in Greece and Yugoslavia failed, because Bulgaria was "not in a position to argue".
Mihailov was in Zagreb serving as an adviser to Ante Pavelić where he was pushing for the formation of volunteer units to operate in what is now the Greek province of Macedonia under Schutzstaffel (SS) command.
Bulgaria immediately ordered its troops to prepare for withdrawal from former Yugoslavia and on 8 September, the Bulgarians changed sides and joined the Soviet Union.
[38] Despite some difficulties in cooperation between the two forces, the Bulgarians worked in conjunction with the Yugoslav Partisans in Macedonia, and managed to delay the German withdrawal through the region by ten to twelve days.
[39] However, under the political pressure of the Partisans, after the liberation of Vardar Macedonia, the Second and Fourth Bulgarian armies were forced to retreat back to the old borders of Bulgaria at the end of November.
[40] Subsequently, to wipe out the remaining Bulgarophile sentiments, the new Communist authorities persecuted the right-wing nationalists with the charges of "great-Bulgarian chauvinism".