The Principality of Bulgaria (Bulgarian: Княжество България, romanized: Knyazhestvo Balgariya) was a vassal state under the suzerainty of the Ottoman Empire.

However, the United Kingdom and Austria-Hungary were against the establishment of such a large Russian client state in the Balkans, fearing it would shift the balance of power in the Mediterranean.

In 1885, a bloodless revolution resulted in Eastern Rumelia being de facto annexed by Bulgaria, which the Ottoman Empire accepted with the Tophane Agreement.

A widely autonomous Principality of Bulgaria was created, between the Danube and the Stara Planina range, with its seat at the old Bulgarian capital of Veliko Turnovo, and including Sofia.

An autonomous Ottoman province under the name of Eastern Rumelia was created south of the Stara Planina range, whereas Macedonia was returned under the sovereignty of the Sultan.

[citation needed] The Bulgarians adopted an advanced democratic constitution, and power soon passed to the Liberal Party led by Stefan Stambolov.

Prince Alexander had conservative leanings, and at first opposed Stambolov's policies, but by 1885 he had become sufficiently sympathetic to his new country to change his mind, and supported the Liberals.

[citation needed] At the end of the century, changes in taxation policy resulted in extensive peasant unrest, primarily centered in northeastern Bulgaria.

At the end of 19th century the Internal Macedonian-Adrianople Revolutionary Organization was founded and began the preparation of an armed uprising in the regions still occupied by the Ottoman Turks.

Its aim was to liberate those regions, or at least to draw the attention of the Great Powers and make them advocate for the improvement of the living conditions for the population through legal and economic reforms.