Samuel of Bulgaria in the context of "Heart attack"

The Byzantine–Bulgarian wars were a series of conflicts fought between the Byzantine Empire and the Bulgarian Empire which began after the Bulgars conquered parts of the Balkan peninsula after 680 AD. The Byzantine and First Bulgarian Empire continued to clash over the next century with varying success, until the Bulgarians, led by Krum, inflicted a series of crushing defeats on the Byzantines. After Krum died in 814, his son Omurtag negotiated a thirty-year peace treaty. Simeon I had multiple successful campaigns against the Byzantines during his rule from 893 to 927. His son Peter I negotiated another long-lasting peace treaty. His rule was followed by a period of decline of the Bulgarian state.

In 971 John I Tzimiskes, the Byzantine emperor, subjugated much of the weakening Bulgarian Empire by defeating Boris II and capturing Preslav, the Bulgarian capital. Samuel managed to stabilize the Bulgarian state with its center around the town of Prespa. Near the end of his rule, the Byzantines regained the upper hand, and under Basil II they won the Battle of Kleidion and completely conquered Bulgaria in 1018. There were rebellions against Byzantine rule from 1040 to 1041, and in the 1070s and the 1080s, but these failed. In 1185, however, Theodore Peter and Ivan Asen started a revolt, and the weakening Byzantine Empire, facing internal dynastic troubles of its own, was unable to quash the revolt.

Krum's dynasty (Bulgarian: Крумова династия) was the royal and later imperial family founded by the Khan of Bulgaria Krum (r. 803–814), producing the monarchs of First Bulgarian Empire between 803 and 991. During this period Bulgaria adopted Christianity, reached its greatest territorial extent and triggered a golden age of culture and literature. Under the patronage of these monarchs Bulgaria became the birthplace of the Cyrillic alphabet; Old Bulgarian became the lingua franca of much of Eastern Europe and it came to be known as Old Church Slavonic. As a result of the victory in the Byzantine–Bulgarian war of 913–927 the Byzantine Empire recognized the imperial title of the Bulgarian rulers and the Bulgarian Orthodox Church as an independent Patriarchate.

The last representative of the dynasty, Tsar Roman (r. 977–991), was succeeded by Tsar Samuel (r. 997–1014) of the Cometopuli dynasty, upon the former's death in Byzantine captivity in 997, after spending six years in prison. Samuel had made the last member of Krum's dynasty a nominal head of state in 977, in order to avoid conflict.

The Battle of Kleidion (Ancient Greek: Κλειδίον; or Clidium, after the medieval name of the village of Klyuch, lit. 'key'; also known as the Battle of Belasitsa) took place on 29 July 1014, between the Byzantine Empire and the Bulgarian Empire. It was the culmination of the nearly half-century struggle between the Byzantine Emperor Basil II and the Bulgarian emperor Samuel in the late 10th and early 11th centuries. The result was a decisive Byzantine victory.

The battle took place in the valley between the mountains of Belasitsa and Ograzhden, near the modern Bulgarian village of Klyuch. The decisive encounter occurred on 29 July with an attack in the rear by a force under the Byzantine general Nikephoros Xiphias, who had infiltrated the Bulgarian positions. The ensuing battle was a major defeat for the Bulgarians. Thousands of Bulgarian soldiers were captured and blinded by order of Basil II, who would subsequently be known as the "Bulgar-Slayer". Samuel survived the battle, but died two months later from a heart attack, reportedly brought on by the sight of his blind soldiers.

The Kometopuli dynasty (Bulgarian: Династия на комитопулите, Dinastiya na komitopulite; Byzantine Greek: Δυναστεία Κομητoπούλων, Dynasteía Kometopoulon) was the last royal dynasty in the First Bulgarian Empire, ruling from c. 976 until the fall of Bulgaria under Byzantine rule in 1018. The most notable member of the dynasty, Tsar Samuel, is famous for successfully resisting Byzantine conquest for more than 40 years. Sometimes the realm of the Cometopuli is called Western Bulgarian Kingdom or Western Bulgarian Empire.

From c. 970 until 1018, a series of conflicts between the Bulgarian Empire and the Byzantine Empire led to the gradual reconquest of Bulgaria by the Byzantines, who thus re-established their control over the entire Balkan peninsula for the first time since the 7th-century Slavic invasions. The struggle began with the incorporation of eastern Bulgaria after the Russo-Byzantine War (970–971). Bulgarian resistance was led by the Cometopuli brothers, who – based in the unconquered western regions of the Bulgarian Empire – led it until its fall under Byzantine rule in 1018.

As the Byzantine-Bulgarian relations deteriorated by the end of the 960s, the Eastern Roman Empire paid the Kievan prince Sviatoslav to attack Bulgaria. The unexpected collapse of Bulgaria and Sviatoslav's ambitions to seize Constantinople caught the Eastern Roman Empire off-guard but they managed to pull back the Kievan armies and occupied eastern Bulgaria including the capital Preslav in 971. Emperor Boris II was captured and taken to Constantinople where he abdicated and the Byzantine Emperor John I Tzimiskes announced the annexation of Bulgaria, even though the Eastern Roman Empire only controlled Eastern Bulgaria at the time, and the lands to the west remained under Bulgarian control. The four brothers David, Moses, Aron, and Samuel of the Cometopuli dynasty ruled in the free territories and in 976, launched a major offensive against the Byzantines to regain the lost lands. Soon, the youngest brother, Samuel, took complete authority following the deaths of his three eldest brothers.

The Theme of Bulgaria (Greek: Θέμα Βουλγαρίας, romanized: Thema Boulgarias) was a theme (province) of the Byzantine Empire established by Emperor Basil II after the conquest of Bulgaria in 1018. Its capital was Skopje and it was governed by a strategos. The theme of Bulgaria did not encompass the old Bulgarian lands between the Haimos Mountains and the river Danube, that included the former capitals Pliska and Preslav. This territory was administered independently and was considered as autonomous military unit, designated as Paristrion or Paradunavon, meaning the "lands beside the Danube".

The local inhabitants were called Bulgarians, but some authors maintain this name did not have an ethnic meaning. Bulgaroi was a political name, in the same way as Romaioi. The emotive force which the name has today is quite distinct from that which inspired the emperors John I and Basil II to celebrate their victories with elaborate ceremony. Their achievement was to restore the empire to her ancient limits, and eliminate the rival, distinct, independent empire that had emerged from the Byzantine model and had been established and recognized within those limits. It can be seen from the fact that the rebels in the Uprising of 1072 invited a Serbian king from Diokleia Constantine Bodin, which belonged to the former empires of Simeon I of Bulgaria and Samuel of Bulgaria, to be the Tsar of the Bulgarians. However, some authors suggest that Bodin was invited, because he was the great-great-grandson of Samuel of Bulgaria.