The Roman province of Macedonia (Latin:Provincia Macedoniae, Greek:Ἐπαρχία Μακεδονίας) was officially established in 146 BC, after the Roman general Quintus Caecilius Metellus defeated Andriscus of Macedon, the last self-styled King of the ancient kingdom of Macedonia in 148 BC, and after the four client republics (the "tetrarchy") established by Rome in the region were dissolved. The province incorporated ancient Macedonia, with the addition of Epirus, Thessaly, and parts of Illyria, Paeonia and Thrace. This created a much larger administrative area, to which the name of 'Macedonia' was still applied. The Dardanians, to the north of the Paeonians, were not included, because they had supported the Romans in their conquest of Macedonia.
After the reforms of Diocletian in the late 3rd century, Epirus Vetus was split off, and sometime in the 4th century, the province of Macedonia itself was divided into Macedonia Prima in the south and Macedonia Secunda or Salutaris in the north. These provinces were all subordinate to the Diocese of Macedonia, one of three dioceses comprising the praetorian prefecture of Illyricum. When the Prefecture was divided between the Western and Eastern Empires in 379, the Macedonian provinces were included in Eastern Illyricum. With the permanent division of the Empire in 395, Macedonia passed to the East, which would evolve into the Byzantine Empire.
In September 1944, Nazi Germany briefly sought to establish an Independent State of Macedonia a puppet state in the territory of the Kingdom of Yugoslavia that had been occupied by the Kingdom of Bulgaria following the invasion of Yugoslavia in April 1941. When Soviet Union forces approached the borders of Bulgaria near the end of August 1944, Bulgaria declared neutrality and briefly sought to negotiate with the Western Allies. As the Bulgarian government was not impeding the withdrawal of German forces from Bulgaria or Romania, that forced the Soviet Union to treat it with suspicion. On 2 September a new pro-Western government took power in Sofia, only to be replaced a week later by a pro-communist government after a Fatherland Front–led revolt. However, on 5 September 1944, the Soviets declared war on Bulgaria.
The person that the Germans turned to in order to implement this scheme was Ivan Mihailov. Mihailov was a Bulgarophile right-wing politician and former leader of the Internal Macedonian Revolutionary Organization (IMRO) that had been engaged in terrorist activity in Yugoslav and Greek Macedonia. Mihailov had become leader of IMRO in 1927 and under his leadership the organisation had joined forces with the Croatian Ustaše in 1929. The two organisations had planned and executed the assassination of King Alexander of Yugoslavia in 1934. After the military coup d'état in the same year IMRO was banned by the authorities. Mihailov fled to Turkey and then Italy, where most of the Ustaše were also in exile. After the invasion of Yugoslavia in 1941, Mihailov had moved to Zagreb where he had acted as an advisor to Ante Pavelić. 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 annexed by the Bulgarians in 1941.