The relations of Greece with her northern neighbours went through a particularly difficult period in the mid-1920s, the basic reason being the issue of minority populations. The partition of Ottoman Macedonia, a multicultural mosaic of peoples and nationalities, created intractable problems among neighbouring national states. In September 1924, during the proceedings of the meeting of the League of Nations, Politis and Kalfof, representatives of Greece and Bulgaria respectively, proceeded to a regulation of their reciprocal obligations towards minorities.
In this framework, the two countries basically accepted the indirect arbitration of third parties in relation to problems and minorities in their territory. The notification of the terms of agreement caused strong agitation in the Greek political world but also in the public opinion of the country. It was considered a personal mistake by Nikolaos Politis, who had been given freedom of movement by the Greek government. There was no agreement as regards the exact motives of the Greek diplomat and the terms of the signing of the protocol. Nevertheless its annulment, on the initiative of Venizelos, had a wide and unfavourable impact on the relations of the country with its northern neighbours. A chain of consequences followed. Yugoslavia reacted first by denouncing the Greek-Serbian Treaty of Alliance of 1913. Greece's appeal to the League of Nations, with the objective of refusing to accept the agreement, caused new friction in Greek-Bulgarian relations, culminating in the incident of 1925.