The First Bulgarian Empire ruled the eastern Balkans from 681 to 1018, converted to Christianity, gave the Slavs their alphabet, and was annexed by Basil II after a war of thirty years.
The First Bulgarian Empire was founded on the lower Danube in 681 and lasted until 1018 — three and a half centuries during which it was the Byzantine empire's most persistent European neighbour, its most dangerous one, and eventually its province.
It began as a steppe khanate: Bulgar horsemen under Asparuh who crossed the Danube, beat a Roman army, and settled among a Slavic population they came to rule and eventually to merge with.
It ended as a Christian, Slavonic-speaking empire whose ruler claimed the title of emperor and whose churchmen created the written language of Orthodox Slavdom — which is why its cultural afterlife is larger than its political record.
The Bulgars were a Turkic steppe people who moved west from the Pontic grasslands under pressure from the Khazars. In 680 Asparuh crossed the Danube into imperial territory, and the emperor Constantine IV led an expedition to remove him.
The campaign failed badly, and in 681 the empire signed a treaty recognising Bulgar control of the lands between the Danube and the Balkan range, and agreeing to pay tribute. It is one of the very few occasions on which Constantinople formally conceded imperial territory to a new state on its own doorstep.
The new khanate ruled a majority Slavic population from a capital at Pliska, and the relationship between the Bulgar ruling group and its Slavic subjects — which ended in a fused, Slavic-speaking people — is the central social fact of its history.
The eighth and early ninth centuries were a long contest with the empire, and Bulgaria won more of it than the Byzantine sources like to admit. Tervel intervened decisively in imperial politics and, by one tradition, at the Arab siege of Constantinople in 718.
Krum, who ruled from about 803 to 814, is the most formidable of them. He destroyed the emperor Nikephoros I and his army in a mountain pass in 811 — the first emperor killed by a foreign enemy since 378 — and had the skull mounted in silver as a drinking cup, an act the Byzantine tradition never forgot.
His successors consolidated rather than expanded. Omurtag built in stone, kept the peace, and left inscriptions in Greek recording his treaties, which are among the best evidence for how the early Bulgarian state actually worked.
Boris I accepted Christianity from Constantinople in 864, choosing the Byzantine church over the Frankish one after playing them against each other, and imposed it on a nobility that revolted and was destroyed for it.
The decision that mattered more came next. When the disciples of Cyril and Methodius were expelled from Moravia, Boris took them in, and the schools at Preslav and Ohrid developed their work into the Cyrillic alphabet and a full Slavonic liturgy and literature.
This is Bulgaria's largest contribution to European history. Old Church Slavonic became the liturgical and literary language of the Orthodox Slavs — Serbia, Rus' and eventually Russia — and the alphabet is still in use from Sofia to Vladivostok.
Asparuh (c. 681–700) founded the state on the Danube. Tervel (700–721) made and unmade Byzantine emperors and campaigned as far as Constantinople.
Krum (c. 803–814) destroyed Nikephoros I and his army in 811 and nearly took the capital. Boris I (852–889) converted the country and sheltered the Slavonic mission. Simeon I (893–927) is the golden age: educated in Constantinople, he fought the empire for thirty years, took the title tsar, and turned Preslav into a capital of letters.
Peter I (927–969) kept a long peace. Samuel (997–1014), of the later western dynasty, fought Basil II for thirty years, and Ivan Vladislav (1015–1018) was the last, dying at Dyrrhachium in the year the empire ended.
Simeon I is the ruler who forced the Byzantines to take Bulgaria seriously as a rival rather than a nuisance. He had been educated in Constantinople, spoke and wrote Greek, and understood exactly what imperial legitimacy consisted of.
He beat Byzantine armies repeatedly, appeared before the walls of Constantinople, and extracted recognition as basileus — emperor — of the Bulgarians. No other medieval ruler in Europe obtained that concession from Constantinople.
His Preslav was a deliberate rival capital, with a golden church, a literary school and a court modelled on the one he had studied in. The claim did not survive him intact, but the precedent did.