Throughout the 8th century the Bulgarian state strengthened and during the Second Arab Siege of Constantinople the country succeeded in becoming a major military power. By the late 800's Eastern Orthodox Christianity had been introduced, as well as the Cyrillic alphabet.
This golden age for Bulgaria continued on through the early 10th century, and under the rule of Simeon the Great the country witnessed a monumental expansion of its borders.
However, after the death of Simeon in 927 AD, Bulgaria's once dominant state of power began to crumble through various wars. And by 1014 the Byzantine's conquered the weakened country, ending the First Bulgarian Empire.
In 1185 the Second Bulgarian Empire formed after a major uprising involving Ivan Asen and Peter IV. The Asen dynasty produced a consistent cultural and economic growth, but was short lived. After a three month siege the Ottomans took control of the Bulgarian Empire in 1393.
For the next five centuries, under Ottoman rule, Bulgaria became an oppressed nation isolated from the rest of Europe. The country struggled through rebellions, and finally in 1876, a large uprising pushed the powers that be to take action.
In 1877, supported by the Bulgarians, the Russian Army defeated the Ottoman's during the Russo-Turkish War, and proposed the Treaty of San Stefano to create an autonomous Bulgarian district.
Although rejected by the Greater Powers, the Treaty of Berlin gave Bulgaria a smaller state which included Moesia and the region of Sofia, and finally on October 5, 1908, they declared themselves once-again officially independent.