Dear Student,
Nationalist tension emerged in the Balkans because:
1. It was a geographically and ethnically diverse region comprising of modern day Romania, Bulgaria, Albania, Greece, Macedonia, Croatia, Bosnia - Herzegovina, Slovenia, Serbia and Montenegro.
2. Spreading of ideas of romantic nationalism along with historical notions of independence.
3. Disintegration of the Ottoman Empire which was a stabilising force in the region.
4. Conflicting ambition of Balkan nationalities which hoped to gain more territory at the expense of others. It led to the region becoming a scene of big power rivalry.
Regards