One of Kubrat's successors, Asparuh, leading some of the Bulgar tribes settled in the area around the Danube delta, and subsequently conquered Scythia Minor and Moesia Inferior from the Byzantine Empire, expanding his new kingdom further into the Balkan peninsula.
[6] Its ethnically and culturally diverse people united under a common religion, language and alphabet which formed and preserved the Bulgarian national consciousness despite foreign invasions and influences.
After reaching its apogee in the 1230s, Bulgaria started to decline due to a number of factors, most notably its geographic position which rendered it vulnerable to simultaneous attacks and invasions from many sides.
By the 19th century, the Bulgarian National Revival became a key component of the struggle for independence, which would culminate in the failed April uprising in 1876, which prompted the Russo-Turkish War of 1877–78 and the subsequent Liberation of Bulgaria.
[18] The Thracians were generally disorganized, but had an advanced culture despite the lack of their own proper script, and gathered powerful military forces when their divided tribes formed unions under the pressure of external threats.
Located in present-day Bulgaria, southeastern Romania (northern Dobruja), northeastern Greece and European Turkey, it was a tribal amalgam dominated by the Odrysians that was the first large political entity to develop in the eastern Balkans.
At the commencement of the Peloponnesian war, Sitalces entered into alliance with the Athenians, and in 429 BC he invaded Macedon (then ruled by Perdiccas II) with a vast army that included 150,000 warriors from independent Thracian tribes.
[43] The Bulgars were a semi-nomadic people of Turkic descent, originally from Central Asia, who from the 2nd century onwards dwelled in the steppes north of the Caucasus and around the banks of river Volga (then Itil).
After a successful war with Byzantium in 680, Asparuh's khanate conquered initially Scythia Minor and was recognised as an independent state under the subsequent treaty signed with the Byzantine Empire in 681.
The successor, Leo III the Isaurian had to deal with an army of 100,000 Arabs led by Maslama ibn Abd al-Malik and a fleet of 2,500 ships that were laying siege on Constantinople in the year 717.
Under the reign of Krum (802–814) Bulgaria expanded vastly north-west and south, occupying the lands between the middle Danube and Moldova rivers, all of present-day Romania, Sofia in 809 and Adrianople in 813, and threatening Constantinople itself.
By the late 9th and early 10th centuries, Bulgaria extended to Epirus and Thessaly in the south, Bosnia in the west and controlled all of present-day Romania and eastern Hungary to the north reuniting with old roots.
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.
Secondly, 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 Samuil, their property and other privileges.
Resurrected Bulgaria occupied the territory between the Black Sea, the Danube and Stara Planina, including a part of eastern Macedonia, Belgrade and the valley of the Morava.
Ivan Asen II had a reputation as a wise and humane ruler, and opened relations with the Catholic west, especially Venice and Genoa, to reduce the influence of the Byzantines over his country.
[66] As Simeon the Great during the first empire, Ivan Asen II expanded the territory to the coasts of three seas (Adriatic, Aegean and Black), annexed Medea - the last fortress before the walls of Constantinople, unsuccessfully besieged the city in 1235 and restored the destroyed since 1018 Bulgarian Patriarchate.
The country's military and economic might declined after the end of the Asen dynasty in 1257, facing internal conflicts, constant Byzantine and Hungarian attacks and Mongol domination.
By 1371, factional divisions between the feudal landlords and the spread of Bogomilism had caused the Second Bulgarian Empire to split into three small tsardoms—Vidin, Tarnovo and Karvuna—and several semi-independent principalities that fought among themselves, and also with Byzantines, Hungarians, Serbs, Venetians and Genoese.
This revision left large populations of ethnic Bulgarians outside the new country and defined Bulgaria's militaristic approach to foreign affairs and its participation in four wars during the first half of the 20th century.
As a result of Stambolov's tactics, the Sultan recognised Bulgarians as the predominant people in Macedonia and gave a green light to the creation of a strong church and cultural institutions.
His domestic policy was distinguished by the defeat of terrorist groups sponsored by Russia, the strengthening of the rule of law, and rapid economic and educational growth, leading to progressive social and cultural change, and development of a modern army capable of protecting Bulgaria's independence.
In 1911, Nationalist Prime Minister Ivan Geshov formed an alliance with Greece and Serbia to jointly attack the Ottomans and revise the existing agreements around ethnic lines.
[90] By 1917, Bulgaria fielded more than a quarter of its 4.5 million population in a 1,200,000-strong army,[91][92] and inflicted heavy losses on Serbia (Kaymakchalan), Great Britain (Doiran), France (Monastir), the Russian Empire (Dobrich) and the Kingdom of Romania (Tutrakan).
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.
[citation needed] But it was clear that the central geopolitical position of Bulgaria in the Balkans would inevitably lead to strong external pressure by both sides of World War II.
[96] Bulgaria succeeded in negotiating a recovery of Southern Dobruja, part of Romania since 1913, in the Axis-sponsored Treaty of Craiova on 7 September 1940, which reinforced Bulgarian hopes for solving territorial problems without direct involvement in the war.
[98] Bulgaria sent occupation forces into eastern Serbia, Macedonia and northern Greece (territories it claimed as its own), where atrocities were committed and local Jews were sent to death camps.
[112] By the time the impact of Mikhail Gorbachev's reform program in the Soviet Union was felt in Bulgaria in the late 1980s, the Communists, like their leader, had grown too feeble to resist the demand for change for long.
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".