The fact is that about 48,000 Jews in Bulgaria proper were spared the Nazi gas chambers and 11,343 Jews from the Bulgarian-administered territories in Macedonia, Aegean Thrace and southern Serbia were not. While the details of the latter seem to be well-known at least internationally, the reasons for and the exact sequence of events leading up to the former remain, at best, contentious.

Up until the beginning of 1943 the Bulgarian Government was preparing itself for the implementation of the Wannsee Conference guidelines to exterminate Europe's Jews.

In July 1942 the Bulgarian Parliament adopted legislation to enable the government to make crucial decisions without parliamentary endorsement. Most historians agree that one of the purposes of this act was to pave the way for the deportation of all of Bulgaria's Jews to Auschwitz and Treblinka. In early March 1943 the government started rounding up 7,122 Jews from Macedonia, 4,221 from Thrace and 185 from the area of Pirot, now in Serbia. These people were herded into Bulgarian State Railways cattle-cars and shipped to Poland, either through Yugoslavian territory or through the Bulgarian port of Lom on the Danube. In keeping with a secret agreement with Theodor Dannecker, on 9 March 1943 Jewish families listed as "undesirable" were rounded up in Kyustendil, Dupnitsa, Gorna Dzhumaya (now Blagoevgrad), Plovdiv and Pazardzhik. Miraculously, the trains prepared for them never departed.

A few days prior to 9 March 1943, Lilyana Panitsa, the personal assistant to Aleksandar Belev, the head of the Jewish Affairs Commissariat, told some Jewish friends about the planned deportations. The news spread quickly and reached four MPs for Kyustendil, one of the towns whose Jews had been on the departure lists. The four consulted with Dimitar Peshev, himself from Kyustendil and deputy speaker of the National Assembly. They decided that the deportations ought to be stopped, and collectively put pressure on Interior Minister Petar Gabrovski. The trains were halted.

But in those days official orders did not travel as fast as they do today. Some provincial authorities remained unaware of the changed plans. One example was Plovdiv. On the night of 10 March 1943 Jews were already being assembled in the Jewish school. Enraged, Kiril, the Orthodox bishop of Plovdiv, stormed into the school and threatened the police that if they went ahead with the deportation he would open up his churches for Jewish refugees and would hide Jews in his own home.

The planned deportations were halted, but Dimitar Peshev had no illusions that the decision was final. On 17 March 1943 he sent a declaration to Prime Minister Bogdan Filov protesting against his anti-Jewish policies. The declaration was signed by 43 MPs from the ruling majority.

Dimitar Peshev was sacked from his parliamentary position on 26 March 1943. Two months later the government made a new attempt to deport the Bulgarian Jews to Nazi-occupied Poland. Aleksandar Belev had two plans. According to Plan A, all 48,000 Jews were to be shipped in one go. Plan B was more "delicate." It envisaged initially deporting 23,000 Sofia Jews to the provinces, and then rounding up everyone and shipping them to Poland. King Boris favoured Plan B. Aleksandar Belev commissioned six ships at Lom and Somovit to carry the human cargo.