The conception of an alliance of the Balkan states, which was to constitute a foundation of permanent cooperation and which dated back to the midnineteenth century, remained unrealised until 1912. The main obstacles included national interests, which frequently antagonised the countries involved, and the ingenious policy conducted by the European powers, which consistently shattered all attempts at an arrangement that could prove detrimental to their interests. For a long time, the socalled Macedonian question made it impossible for the Balkan states to reach a suitable agreement. An atmosphere conducive for the establishment of an allBalkan union was created by the Bosnian crisis. The step taken against the status quo by AustroHungary - up to then one of the prime pillars of the so called Berlin order - made Balkan politicians aware of the possibility of territorial changes on the Peninsula. This was one of the reasons for the establishment of the Balkan Bloc in 1912. It must be additionally emphasised that although the Balkan alliance of 1912 should be regarded as an unmistakable diplomatic success, its members did not manage to avoid errors well known from the past. The most important impediment was the limited opportunity for creating a chain of bilateral conventions. Already in 1912 the signatories squandered chances for longer cooperation by resigning from an allBalkan agreement that would delineate the range of the activity of the particular members and the sphere of their impact.