Present-day Bulgaria is inhabited by the Thracians until the first century BC. At that time Thracia is conquered by the Roman Empire. After the division of the Roman Empire Thracia becomes in 379 part of the East Roman Empire. In 681 the Turkish-Tatarian people of the Bulgarians enter Thracia, defeat the East Romans and establish Bulgaria, a mixture of Slavs and Bulgars. This develops into the first Kingdom of Bulgaria in 893. In 1018,Bulgaria fell again under the authority of the East Roman Empire. By 1185 Bulgarians break free of East Roman rule and in 1202 the second Kingdom of Bulgaria is a fact. In 1396 Bulgaria is annexed by the Ottoman Empire.

In 1878 Bulgaria becomes the Principality of Bulgaria, although under Ottoman suzerainty. The first prince is elected by parliament, Alexander of Battenberg. Politics is dominated by the conservative and liberal parties. The principality is a constitutional monarchy, which acquires Eastern Rumelia in 1885. In 1886 a group of Russian and Bulgarian conspirators abduct Prince Alexander and the liberal prime minister Petko Karavelov and establish a Russian-dominated government. This government is overthrown by Stepan Stambolov of the conservative liberal Narodnoliberalna Partija (People's Liberal Party, NLP) in 1887. A new ruler is elected, Prince Ferdinand of Saxe-Coburg-Gotha. Stambolov remains prime minister until 1894. He is succeeded from 1894 until 1899 by Konstantin Stoilov of the conservative Narodna Partija (National Party, NP). Since 1899 the premiership changes very quickly. A longer premiership have the military Racho Petrov (1903-1906) and Aleksandur Malinov of the liberal Demokratička Partija (Democratic Party, DP) (1908-1911).

Full independence is gained in 1908 when becomes Tsardom of Bulgaria. Malinov is succeeded in 1911 by Ivan Evstratiev Gešev of the NP. In the First Balkan War (1912-1913), Bulgaria defeats with its allies Serbia, Montenegro and Greece the Ottoman Empire. In 1913 Vasil Radoslavov of the conservative Liberalna-Radoslavistka Partija (Liberal Party Radosvavists) becomes prime minister. The parties cannot agree on the division of the reconquered Balkan territories, which results the Second Balkan War in 1913. That war is lost by Bulgaria: as a consequence it loses large parts of the newly gained territory. Being an ally of Germany and Austria in World War I, it loses after the war most of what it had gained in the Balkan Wars. Aleksandur Malinov becomes prime minister again in 1918, succeeded later that year by Teodor Teodorov. Aleksandur Stambolijski of the Balgarski Zemedelski Naroden Sajuz (Bulgarian Agrarian People's Union, BZNS) becomes prime minister in 1919. He strives after an improvement of the condition of the large peasant class. Stambolisky’s dictatorial regime is overthrown by a coup etat in 1923, during which he is assassinated. The coup brings Aleksandur Cankov of the alliance Demokratičeski Sgovor (Democratic Unity, DS) to power. In 1926 he is succeeded by Andrej Ljapčev, former member of the DP, now leading the DS. The DS is defeated at the elections of 1931 and after a short premiership by DP leader Aleksandur Malinov Nikola Mušanov of the DP becomes prime minister in a coalition of his DP, the Radikalna Partija (Radical Party, RP) and factions of the BZNS. In 1934 the army together with the populist movement Zveno stage a coup. Kimon Georgiev becomes prime minister and all other barires are banned. In 1935 Tsar Boris stages a coup of his own and establishes a royal dictatorship. In 1941 under German pressure Bulgaria joins the Axis powers. Tsar Boris dies in 1943 and his six-year old son, Simeon II, becomes tasar. A pro-German government is formed by Dobri Bozhilov. This regime falls in 1944 and Bulgaria is occupied by the USSR.

The opposition parties boycot the elections of 1945 and a single list of candidates of the Communist-dominated Fatherland Front wins 85 percent of the vote. Tsar Simeon II goes into exile in 1946. By 1946 Bulgaria, named People's Republic of Bulgaria, has become a satellite of the Soviet Union, remaining so throughout the Cold War period. Bulgaria is ruled by the Bălgarska Komunističeska Partija (Bulgarian Communist Party, BKP) of Georgi Dimitrov. Dimitrov is succeeded in 1954 by Todor Živkov. The communist dictatorship collapses in 1990.

An alliance of opposition parties, the Sajuz na Demokratičnite Sili (Union of Democratic Forces, SDS), doesn't succeed in winning the elections and the successor of the BKP, the Bălgarska Socialističeska Partija (Bulgarian Socialist Party, BSP) gets a clear majority. The country is renamed Republic of Bulgaria in 1991 and becomes a parliamentary democracy. After new elections that year, the SDS becomes the largest party and Filip Dimitrov becomes prime minister. He loses support in parliament and is succeeded by the non-partisan Ljuben Berov. In 1994 the BSP wins the elections and žan Videnov becomes prime minister. When Petar Stojanov of the SDS wins the presidential elections of 1996, Videnov resigns and new elections are held in 1997. These are won by the SDS and allies. Ivan Kostov of the SDS becomes prime minister and he leads a stable government. Nevertheless the SDS loses the 2001 parliamentary elections. The Nacionalno Dviženie Simeon Vtori (National Movement Simeon II, NDSV) becomes the largest party and its leader, former king Simeon Borisov Sakskoburggotski becomes prime minister.