The geographical area of Macedonia has been the first line of defense and counterattack for Hellenism since ancient times, from the era of the Persian Wars.
In more recent times, it has been an area of increased interest for tsarist Russian foreign policy, whose acknowledged goal was to gain access to the Aegean Sea. This strategic choice led to the involvement and instigation, from the mid-19th century (the Crimean War being a pivotal point and the imprint of its consequences in the Balkans), on the one hand, primarily of Bulgarian expansionism and, secondarily, of Serbian expansionism, by exploiting the ideology of Pan-Slavism, so that their own geopolitical goals could be served, even indirectly, through the occupation of Macedonia.
The Soviet regime that succeeded the tsarist rule did not change its objectives. With the invention of the "Balkan Communist Federation," it sought to detach Macedonia and Thrace from the Greek state in order to achieve the aforementioned goal.
However, these methods led to an unexpected reality that worked counterproductively to the initial plans: The claim for Macedonia became incorporated into the national aspirations and demands of both the Serbs and the Bulgarians, who attempted to implement it with different tactics and in different historical circumstances.