The Principality of Bulgaria existed between 1878 and 1908. It was created at the Congress of Berlin, from parts of the Ottoman Empire. It was a vassal state of the Ottoman Empire, and had to pay tribute. The capital was Sofia. The area that is now southern Bulgaria, became a province called Eastern Rumelia.In 1878, there were uprisings, which were brutally suppressed. In 1885, Eastern Rumelia merged to the Principality of Bulgaria, An uprising in Plovdiv started this. This merger was done against the will of Russia, and other European powers. In 1908, the Ottoman Empire ecognised the independence of the Principality, and it became a kingdom. Ferdinand I (who had ruiled the state before, became tsar, or king.