The treaty of San Stefano restored Bulgaria as a powerful state on the Balkans encompassing all the lands populated by Bulgarians and ruled by the idealistic Alexander I Battenberg, grandson of Queen Victoria and nephew to the Russian emperor. However, San Stefano Bulgaria was hacked up by the delegate nations at the Congress of Berlin only three months later. Ethnically Bulgarian territories (in striped red on the map) were divided into three distinct regions: the Principality of Bulgaria encompassed only Moesia and the Sofia region, Thrace became semi-autonomous under the name Eastern Rumelia and the status of Macedonia and parts of Thrace remained unchanged: they returned to Ottoman rule and their populations were brutally punished for the short gasp of freedom.
In this manner the Great Powers of Europe sowed the seeds for countless conflicts on the Balkans. Because of the Congress of Berlin, Bulgaria would spend decades struggling to once again unify all the lands considered ethnically Bulgarian in its borders. This struggle would cost it two national catastrophes and sour its relationships with Serbia, Greece and Romania, who’d believe Bulgaria to be motivated by hegemony.
The Principality of Bulgaria and Eastern Rumelia unified in 1885, displeasing the Russian emperor and leading to the eventual abdication of Alexander I. A new tsar was solicited from the Saxe Coburg-Gotha dynasty, a German prince by the name of Ferdinand. His dynasty would rule Bulgaria until the absolution of the monarchy by the Communist party in 1946 and the exile of his grandson, Simeon III, then 9 years old.
This period in Bulgarian history is known for its modernization as a state, incorporating the best of European know-how into its practices: railways, a postal service, industrialization, and the emergence of Sofia and Ruse as cities of culture and architectural beauty.
It was also characterized by two national catastrophes. In sharp contrast to the two Golden Ages of medieval times, each occurred at the conclusion of a conflict that Bulgaria was on the wrong side of.
The first national catastrophe occurred at the end of the Balkan wars (1912-1913). After helping its neighbours push the Ottoman Empire out of many regions of the Balkans in the hopes of reclaiming Bulgarian-inhabited territories, Bulgaria was provoked and defeated by its former allies, resulting in tremendous losses of territory.
Eager to reclaim lost territories, Bulgaria joined the Central powers in 1915. Despite a heroic defence of its Western border, culminating in the brilliantly fought Doiran battles, Bulgaria was on the losing side of the war and lost further territories under the treaty of Neuilly-sur-Seine, leading to the second national catastrophe.
At the onset of the Second World War, Bulgaria found itself in a strategically important position, which allowed it to stall and declare neutrality in the conflict, waiting for the best offer. This strategy worked until Mussolini’s failed attempt to subdue Greece in 1941. This called for Wehrmacht forces to cross Romania and Bulgaria to attack Greece, and put Bulgaria in a position to join the war on the side of the Axis or be conquered. Enticed by promises of territorial unification, Bulgaria sided with Germany and occupied parts of Yugoslavia and Greece, briefly ballooning to a San Stefano-like size.
Once again on the losing side of a conflict, and after having defended Sofia from several bombings by English and American air forces, Bulgaria avoided being steamrolled by the USSR by establishing a Communist government on September 9, 1944, exiting the Axis and joining the war on the Soviet side. After the end of the war, Bulgaria would spend 45 years on the losing side of another conflict: as a satellite state in the Soviet bloc.
As a notable exception to the fates that befell Jewish minorities in Axis-alligned countries, most of the Bulgarian Jewish minority was spared deportation to Germany due to widespread public outcry against it. (Read more about it on the New Politics site.)