In 632 the Bulgars, originally from Central Asia, formed under the leadership of Khan Kubrat an independent state that became known as Great Bulgaria. Its territory extended from the lower course of the Danube to the west, the Black Sea and the Azov Sea to the south, the Kuban River to the east, and the Donets River to the north.Pressure from the Khazars led to the subjugation of Great Bulgaria in the second half of the 7th century. Kubrat’s successor, Khan Asparuh, migrated with some of the Bulgar tribes to the lower courses of the rivers Danube, Dniester and Dniepr (known as Ongal), and conquered Moesia and Scythia Minor (Dobrudzha) from the Byzantine Empire, expanding his new khanate further into the Balkan Peninsula. A peace treaty with Byzantium in 681 and the establishment of the Bulgar capital of Pliska south of the Danube mark the beginning of the First Bulgarian Empire. At the same time one of Asparuh's brothers, Kuber, settled with another Bulgar group in present-day[update] Macedonia.
During the siege of Constantinople in 717-718 the Bulgarian ruler Khan Tervel honoured his treaty with the Byzantines by sending troops to help the populace of the imperial city. According to the Byzantine chronicler Theophanes, in the decisive battle the Bulgarians killed 22,000 Arabs, thereby eliminating the threat of a full-scale Arab invasion into Eastern and Central Europe.
The influence and territorial expansion of Bulgaria increased further during the rule of Khan Krum, who in 811 won a decisive victory against the Byzantine army led by Nicephorus I in the Battle of Pliska.
In 864, Bulgaria under Boris I The Baptist accepted Eastern Orthodox Christianity.
Bulgaria became a major European power in the ninth and the tenth centuries, while fighting with the Byzantine Empire for the control of the Balkans. This happened under the rule (852–889) of Boris I. During his reign, the Cyrillic alphabet was created in Preslav and Ohrid, adapted from the Glagolitic alphabet invented by the monks Saints Cyril and Methodius.
The Cyrillic alphabet became the basis for further cultural development. Centuries later, this alphabet, along with the Old Bulgarian language, fostered the intellectual written language (lingua franca) for Eastern Europe, known as Church Slavonic. The greatest territorial extension of the Bulgarian Empire — covering most of the Balkans — occurred under Emperor Simeon I The Great, the first Bulgarian Tsar (Emperor), son of Boris I.
However, Simeon's greatest achievement consisted of Bulgaria developing a rich, unique Christian Slavonic culture, which became an example for the other Slavonic peoples in Eastern Europe and also ensured the continued existence of the Bulgarian nation despite forces that threatened to tear it into pieces throughout its long and war-ridden history.
Bulgaria declined in the mid-tenth century, worn out by wars with Croatia, by frequent Serbian rebellions sponsored by Byzantine gold, and by disastrous Magyar and Pecheneg invasions. Because of this, Bulgaria collapsed in the face of an assault of the Rus' in 969-971.
The Byzantines then began campaigns to conquer Bulgaria. In 971, they seized the capital Preslav and captured Emperor Boris II.Resistance continued under Tsar Samuil in the western Bulgarian lands for nearly half a century. The country managed to recover and defeated the Byzantines in several major battles, taking the control of the most of the Balkans and in 991 invaded the Serbian state. But the Byzantines led by Basil II ("the Bulgar-Slayer") destroyed the Bulgarian state in 1018 after their victory at Kleidion.
No evidence remains of major resistance or any uprising of the Bulgarian population or nobility in the first decade after the establishment of Byzantine rule. Given the existence of such irreconcilable opponents to Byzantium as Krakra, Nikulitsa, Dragash and others, such apparent passivity seems difficult to explain. Some historians explain this as a consequence of the concessions that Basil II granted the Bulgarian nobility in order to gain their obedience. In the first place, Basil II guaranteed the indivisibility of Bulgaria in its former geographic borders and did not officially abolish the local rule of the Bulgarian nobility, who became part of Byzantine aristocracy as archons or strategoi. Second, special charters (royal decrees) of Basil II recognised the autocephaly of the Bulgarian Archbishopric of Ohrid and set up its boundaries, securing the continuation of the dioceses already existing under Samuel, their property and other privileges.
The people of Bulgaria challenged Byzantine rule several times in the 11th century and again in the early 12th century. The biggest uprising occurred under the leadership of Peter II Delyan (proclaimed Emperor of Bulgaria in Belgrade in 1040). In the mid to late 11th century, the Normans, fresh from their recent conquests in southern Italy and Sicily, landed in the Balkans and began advancing against the Byzantine Empire. They posed a constant threat to Byzantine Bulgaria, and it took Byzantium until 1185 to drive them out. In 1091 another invasion came in the form of the Pechenegs. However, Byzantine forces crushed the Pechenegs at Levounion (1091) and again around 1120. After that, the Hungarians made an attempt to increase their influence beyond the Danube river; John Comnenus' campaigns along the Danube eventually drove back the Hungarians as well by c.1140. Bulgarian nobles ruled the province in the name of the Byzantine Empire until a rebellion by Ivan Asen I and Peter IV of Bulgaria led to the establishment of the Second Bulgarian Empire.
From 1185, the Second Bulgarian Empire once again established Bulgaria as an important power in the Balkans for two more centuries with its capital based in Veliko Tarnovo and under the Asen dynasty. Kaloyan, the third of the Asen monarchs, extended his dominions to Belgrade, Nish and Skopie (Uskub); he acknowledged the spiritual supremacy of the pope, and received the royal crown from a papal legate. The Bulgarian ruler from 1218 to 1241, Ivan Asen II extended his rule over Albania, Epirus, Macedonia and Thrace. During his reign, the state saw a period of cultural growth, with important artistic achievements of the Tarnovo artistic school. The Asen dynasty ended in 1257, and due to Tatar invasions (beginning in the later 13th century), internal conflicts, and constant attacks from the Byzantines and the Hungarians, the power of the country declined. Emperor Theodore Svetoslav (reigned 1300-1322) restored Bulgarian prestige from 1300 onwards. But by the end of the 14th century the country had disintegrated into several feudal principalities, which the Ottoman Empire eventually conquered.
By the end of the 14th century, factional divisions between Bulgarian feudal landlords (boyars) had gravely weakened the cohesion of the Second Bulgarian Empire. It split into three small Tsardoms and several semi-independent principalities which fought among themselves, and also with Byzantines, Hungarians, Serbs, Venetians, and Genoese. In these battles, they often allied with the Ottoman Turks. Similar situations of internecine quarrel and infighting existed also in Byzantium and Serbia. In the period 1365-1370, the Ottomans conquered most Bulgarian towns and fortresses south of the Balkan Mountains.
In 1393, the Ottomans captured Tarnovo, the capital of the Second Bulgarian Empire, after a three-month siege. In 1396, the Vidin Tsardom fell after the defeat of a Christian crusade at the Battle of Nicopolis. With this, the Ottomans finally subjugated and occupied Bulgaria.A Polish-Hungarian crusade commanded by Władysław III of Poland set out to free the Balkans in 1444, but the Turks defeated it in the battle of Varna.
Some accounts of the five centuries of Ottoman rule highlight its violence and oppression. The Ottomans decimated the Bulgarian population, which lost most of its cultural relics. Turkish authorities destroyed most of the medieval Bulgarian fortresses in order to prevent rebellions. Large towns and the areas where Ottoman power predominated remained severely depopulated until the 19th century.
The new authorities dismantled Bulgarian institutions at anything above the village or communal level, and merged the separate Bulgarian Church into the Ecumenical Patriarchate in Constantinople, although a small, autocephalous Bulgarian archbishopric of Ohrid survived until January 1767.
Bulgarians in the Ottoman empire had to endure a number of disabilities; they paid more taxes than Moslems, they lacked legal equality with Moslems, they could not carry arms, their clothes could not rival those of Moslems in color, nor could their churches tower as high as mosques. Bulgarians who converted to Islam, the Pomaks, retained Bulgarian language, dress and some customs compatible with Islam.
The Ottoman system started to decline by the 17th century, and at the end of the 18th had all but collapsed. Central government weakened over the decades, and this had allowed a number of local Ottoman holders of large estates to establish personal ascendancy over separate regions. During the last two decades of the 18th and first decades of the 19th centuries the Balkan Peninsula dissolved into virtual anarchy, a period known in Bulgarian as the kurdjaliistvo. Armed bands of Turks, called kurdjalii, plagued the area at this time. In many regions, thousands of peasants fled from the countryside either to local towns or (more probably) to the hills or forests; some even fled beyond the Danube to Moldova, Wallachia or southern Russia.
In the 18th and especially the 19th centuries conditions improved in certain areas. Some towns — such as Gabrovo, Tryavna, Karlovo, Koprivshtitsa, Lovech, Skopie — prospered. The Bulgarian peasants actually possessed their land, although it officially belonged to the sultan. The 19th century also brought improved communications, transportation and trade. The first factory in the Bulgarian lands opened in Sliven in 1834, and the first railway system started running (between Rousse and Varna) in 1865.
Throughout the five centuries of Ottoman rule, the Bulgarian people organized many attempts to re-establish their own state. The National awakening of Bulgaria became one of the key factors in the struggle for liberation. The 19th century saw the creation of the Bulgarian Revolutionary Central Committee and the Internal Revolutionary Organisation led by liberal revolutionaries such as Vasil Levski, Hristo Botev, Lyuben Karavelov and many others.
In 1876, the April uprising broke out: the largest and best-organized Bulgarian rebellion against the Ottoman Empire. Though crushed by the Ottoman authorities, the uprising (together with the 1875 rebellion in Bosnia) prompted the Great Powers to convene the 1876 Conference of Constantinople, which delimited the ethnic Bulgarian territories as of the late 19th century, and elaborated the legal and political arrangements for establishing two autonomous Bulgarian provinces. The Ottoman Government declined to comply with the Great Powers’ decisions. This allowed Russia to seek a solution by force without risking military confrontation with other Great Powers as in the Crimean War of 1854 to 1856.
In the Russo-Turkish War, 1877-1878, Russian soldiers together with a Romanian expeditionary force and volunteer Bulgarian troops defeated the Ottoman armies. The Treaty of San Stefano (3 March 1878), set up an autonomous Bulgarian principality. But the Western Great Powers immediately rejected the treaty, fearing that a large Slavic country in the Balkans might serve Russian interests. This led to the Treaty of Berlin (1878) which provided for an autonomous Bulgarian principality comprising Moesia and the region of Sofia. Alexander, Prince of Battenberg, became Bulgaria's first Prince.
Most of Thrace became part of the autonomous region of Eastern Rumelia, whereas the rest of Thrace and all of Macedonia returned to the sovereignty of the Ottomans. After the Serbo-Bulgarian War and unification with Eastern Rumelia in 1885, the Bulgarian principality proclaimed itself a fully independent kingdom on 5 October (22 September O.S.), 1908, during the reign of Ferdinand I of Bulgaria.
Ferdinand, of the ducal family of Saxe-Coburg-Gotha, became the Bulgarian Prince after Alexander von Battenberg abdicated in 1886 following a coup d'état staged by pro-Russian army-officers. (Although the counter-coup coordinated by Stefan Stambolov succeeded, Prince Alexander decided not to remain the Bulgarian ruler without the approval of Alexander III of Russia.) The struggle for liberation of the Bulgarians in the Adrianople Vilayet and in Macedonia continued throughout the late 19th and early 20th centuries, culminating with the Ilinden-Preobrazhenie Uprising organised by the Internal Macedonian Revolutionary Organization in 1903.
In 1912 and 1913, Bulgaria became involved in the Balkan Wars, first entering into conflict alongside Greece, Serbia and Montenegro against the Ottoman Empire. The First Balkan War (1912-1913) proved a success for the Bulgarian army, but a conflict over the division of Macedonia arose between the victorious allies. The Second Balkan War (1913) pitted Bulgaria against Greece and Serbia, joined by Romania and Turkey. After its defeat in the Second Balkan War, Bulgaria lost considerable territory conquered in the first war, as well as Southern Dobrudzha and parts of the region of Macedonia.
During World War I, Bulgaria found itself fighting again on the losing side as a result of its alliance with the Central Powers. Defeat in 1918 led to new territorial losses (the Western Outlands to Serbia, Western Thrace to Greece and the re-conquered Southern Dobrudzha to Romania). The Balkan Wars and World War I led to the influx of over 250,000 Bulgarian refugees from Macedonia, Eastern and Western Thrace and Southern Dobrudzha.
In September 1918, Tsar Ferdinand abdicated in favour of his son Boris III in order to head off revolutionary tendencies. Under the Treaty of Neuilly (November 1919) Bulgaria ceded its Aegean coastline to Greece, recognized the existence of Yugoslavia, ceded nearly all of its Macedonian territory to that new state, and had to give Dobrudzha back to Romania. The country had to reduce its army to 20,000 men, and to pay reparations exceeding $400 million. Bulgarians generally refer to the results of the treaty as the "Second National Catastrophe".
Elections in March 1920 gave the Agrarians a large majority, and Aleksandar Stamboliyski formed Bulgaria's first peasant government. He faced huge social problems, but succeeded in carrying out many reforms, although opposition from the middle and upper classes, the landlords and the officers of the army remained powerful. In March 1923, Stamboliyski signed an agreement with the Kingdom of Yugoslavia recognising the new border and agreeing to suppress Internal Macedonian Revolutionary Organization (VMRO), which favoured a war to regain Macedonia from Bulgaria. This triggered a nationalist reaction, and the Bulgarian coup d'état of 9 June 1923 eventually resulted in Stamboliykski's assassination. A right-wing government under Aleksandar Tsankov took power, backed by the army and the VMRO, which waged a White terror against the Agrarians and the Communists. In 1926, the Tsar persuaded Tsankov to resign, a more moderate government under Andrey Lyapchev took office and an amnesty was proclaimed, although the Communists remained banned. A popular alliance including the re-organised Agrarians won elections in 1931 under the name "Popular Bloc".
In May 1934 another coup took place, removing the Popular Bloc from power and establishing an authoritarian military régime headed by Kimon Georgiev. A year later, Tsar Boris managed to remove the military régime from power, restoring a form of parliamentary rule (without the re-establishment of the political parties) and under his own strict control. The Tsar's regime proclaimed neutrality, but gradually Bulgaria gravitated into alliance with Nazi Germany and Fascist Italy.
After regaining control of Southern Dobrudzha in 1940, Bulgaria became allied with the Axis Powers, although it declined to participate in Operation Barbarossa (1941) and never declared war on the USSR. During World War II Nazi Germany allowed Bulgaria to occupy parts of Greece and of Yugoslavia. Bulgaria became one of only three countries (along with Finland and Denmark) that saved its entire Jewish population (around 50,000 people) from the Nazi camps by refusing to comply with a 31 August 1943 resolution.
In early September 1944, the Soviet Union declared war on Bulgaria and invaded the country, meeting no resistance. This enabled the Bulgarian Communists (the Bulgarian Workers' Party) to seize power and establish a communist state. The new régime turned Bulgaria's forces against Germany. The 450,000-man army of 1944 dwindled to 130,000 by 1945. However, the authorities deported almost the entire Jewish population of the Bulgarian-occupied Yugoslav and Greek territories to the Treblinka death camp in occupied Poland.
In World War II Bulgaria had again allied itself with Germany following the promise of the return of Macedonia. On September 8, 1944 the USSR declared war on Bulgaria and crossed the Danube. Bulgarian army officers and partisan brigades joined forces with the Soviets and Sofia fell. On the next day the invading forces took the rest of Bulgaria. (9 September became known as "Liberation Day".) The Fatherland Front took over the government and the Communist party increased its membership from 15,000 to 250,000 during the following six months.
After World War II, Bulgaria fell within the Soviet sphere of influence. It became a People's Republic in 1946 and one of the USSR's staunchest allies. In the late 1970s, it began normalizing relations with Greece. The forced assimilation campaign of the late 1980s directed against ethnic Turks resulted in the emigration of some 300,000 Bulgarian Turks to Turkey. The People's Republic ended in 1989 as many Communist regimes in Eastern Europe, as well as the Soviet Union itself, began to collapse. Opposition forces removed the Bulgarian Communist leader Todor Zhivkov and his right-hand man Milko Balev from power on 10 November 1989.
In February 1990 the Communist Party voluntarily gave up its monopoly on power, and in June 1990 free elections took place, won by the moderate wing of the Communist Party (renamed the Bulgarian Socialist Party — BSP). In July 1991, the country adopted a new constitution which provided for a relatively weak elected President and for a Prime Minister accountable to the legislature.
The anti-Communist Union of Democratic Forces took office, and between 1992 and 1994 carried through the privatization of land and industry, and faced massive unemployment and economic difficulties. The reaction against economic reform allowed BSP to take office again in 1995, but by 1996 the BSP government had also encountered difficulties, and in the presidential elections of that year the UDF's Petar Stoyanov was elected. In 1997, the BSP government collapsed and the UDF came to power. Unemployment remained high and the electorate became increasingly dissatisfied with both parties.
Relations with Turkey began to normalise in the 1990s.
On 17 June 2001, Simeon II, the son of Tsar Boris III and the former Head of state (as Tsar of Bulgaria from 1943 to 1946), won a narrow victory in elections. The Tsar's party — National Movement Simeon II ("NMSII") — won 120 of the 240 seats in Parliament and overturned the two pre-existing political parties. Simeon's popularity declined during his four-year rule as Prime Minister, and the BSP won the elections in 2005, but could not form a single-party government and had to seek a coalition.
Since 1989, Bulgaria has held multi-party elections and privatized its economy, but economic difficulties and a tide of corruption have led over 800,000 Bulgarians, including many qualified professionals, to emigrate in a "brain drain". The reform package introduced in 1997 restored positive economic growth, but led to rising social inequality. Bulgaria became a member of NATO in 2004 and of the European Union in 2007.