Battle of Kleidion (1014): Basil II, the Bulgar Slayer

The Battle of Kleidion was fought on 29 July 1014 in a mountain pass in the south-western Balkans, where the Byzantine emperor Basil II defeated the army of Tsar Samuel of Bulgaria. Basil’s reported blinding of thousands of prisoners became one of the most notorious episodes of the Middle Ages. The defeat broke Bulgarian resistance, and within four years the First Bulgarian Empire had become a Byzantine province.

Background: a long war for the Balkans

Bulgaria had been a major power in south-eastern Europe since its foundation in the late 7th century, described in the article on the founding of the First Bulgarian Empire. Under Simeon the Great in the early 10th century it had even challenged Constantinople. In 971, however, the Byzantine emperor John I Tzimiskes captured the Bulgarian capital Preslav and annexed the eastern part of the country.

Resistance continued in the west. Four brothers, known as the Cometopuli (“sons of the count”), led a revival; by the late 980s the survivor, Samuel, controlled a large realm centred on Ohrid and Prespa in what is now North Macedonia and Albania. He was recognised as tsar around 997.

Samuel inflicted a humiliating defeat on the young emperor Basil II at the Gates of Trajan in 986. For the next two decades the two rulers fought a long war of raids, sieges and campaigns. From around 1001 Basil campaigned in the Balkans almost every year, taking fortresses one by one and steadily shrinking Samuel’s territory.

The pass at Kleidion

By 1014 Samuel decided to block the main route by which Byzantine armies entered his heartland, the valley leading west from the Struma river. The pass, called Kleidion (“the key”) by the Byzantines, lay between the Belasitsa mountains to the south and the Ograzhden range to the north, near the village of Klyuch in modern Bulgaria.

Samuel fortified the pass with earthworks and wooden palisades and stationed a large army behind them. Estimates of his forces vary widely, and medieval figures are unreliable, but the army was clearly substantial. When Basil arrived in the summer of 1014, his frontal attacks on the defences failed.

The battle

The solution came from Nikephoros Xiphias, the Byzantine governor of Philippopolis (modern Plovdiv). He led a detachment on a difficult march over the Belasitsa range by mountain paths, according to Skylitzes on a route that took several days.

On 29 July 1014 Xiphias’s troops descended on the rear of the Bulgarian position. Caught between this force and Basil’s main army, which now attacked the palisades again, the Bulgarians broke. Many were killed and many more were taken prisoner. Samuel escaped, reportedly with the help of his son Gabriel Radomir, and fled to the fortress of Prilep.

The victory was not complete. Shortly afterwards a Byzantine force under Theophylact Botaneiates, sent to clear the route towards Thessalonica, was ambushed in a gorge near Strumica, and Botaneiates was killed. The Bulgarian army, however, had suffered a blow from which it could not recover.

Where exactly was the battle?

The name Kleidion survives in the Bulgarian village of Klyuch, which also means “key”, at the foot of the Belasitsa range in south-western Bulgaria. Most historians place the Bulgarian fortifications in the valley of the Strumeshnitsa river nearby. Because the battlefield is not marked by clear archaeological remains, its exact line is still discussed, and the battle is also known in Bulgarian as the Battle of Belasitsa.

The blinding of the prisoners

What followed made the battle infamous. According to John Skylitzes, Basil ordered the captives to be blinded, about 15,000 men in all, leaving one in every hundred with one eye so that he could lead the others back to Samuel.

Blinding was a recognised punishment in Byzantium, often used against rebels and defeated rivals, but this mass mutilation was exceptional. Historians generally accept that it happened. The figure of 15,000 is more doubtful; it comes from a source written several decades later, and some scholars suggest the real number was lower.

Skylitzes reports that when the blinded men reached Prespa, Samuel fainted at the sight and died two days later, on 6 October 1014. Modern accounts often attribute his death to a stroke or heart attack.

Key people

• Basil II (ruled 976–1025), the most successful Byzantine soldier-emperor of his age.
• Samuel, tsar of Bulgaria from about 997, who resisted Byzantium for almost forty years.
• Nikephoros Xiphias, the general whose outflanking march won the battle.
• Gabriel Radomir, Samuel’s son and briefly his successor.
• Theophylact Botaneiates, the Byzantine commander killed in an ambush after the battle.

Consequences: the fall of Bulgaria

Samuel’s death left Bulgaria divided and demoralised. Gabriel Radomir ruled for less than a year before he was murdered in 1015 by his cousin Ivan Vladislav, who took the throne and continued to fight.

Basil kept up the pressure each year. Ivan Vladislav was killed in February 1018 while besieging the Byzantine city of Dyrrhachium (modern Durrës, Albania). His widow, the leading nobles and the remaining commanders then surrendered, and Basil entered Ohrid in triumph in 1018.

Basil treated the conquered land with some care. Local taxes were allowed to be paid in kind, as before, and the Bulgarian church kept a degree of independence as the autocephalous archbishopric of Ohrid. On his way home Basil celebrated his victory in Athens, giving thanks in the Parthenon, which was then a church of the Virgin.

Byzantine rule over Bulgaria lasted until 1185, when the brothers Asen and Peter rebelled and founded the Second Bulgarian Empire. Basil’s armies, including his Varangian Guard, also helped him expand the empire in the Caucasus, making Byzantium at his death in 1025 the leading power of the eastern Mediterranean.

Myths and facts

Myth: Basil II was called the Bulgar Slayer in his own lifetime. The Greek epithet Boulgaroktonos is not found in contemporary sources. The historian Paul Stephenson has shown that it became popular in the late 12th century, when Byzantium again faced a rebellious Bulgaria, and was revived in Greek nationalism around 1900.

Myth: Kleidion alone destroyed Bulgaria. The battle was decisive, but it came after more than a decade of grinding campaigns, and Bulgarian resistance lasted another four years.

Myth: the numbers are precise. The size of the armies and the number of blinded captives come from later chroniclers and should be treated as approximate.

By the numbers

Timeline

• 971: John I Tzimiskes captures Preslav and annexes eastern Bulgaria.
• 986: Samuel defeats Basil II at the Gates of Trajan.
• c. 997: Samuel is recognised as tsar.
• 1001 onwards: Basil II campaigns in the Balkans almost every year.
• 29 July 1014: Byzantine victory at the Kleidion pass.
• 6 October 1014: Samuel dies at Prespa.
• 1015: Gabriel Radomir is killed by Ivan Vladislav.
• February 1018: Ivan Vladislav dies at Dyrrhachium.
• 1018: Bulgaria submits; Basil II enters Ohrid.

Why it matters

Kleidion decided a struggle that had shaped the Balkans for centuries, bringing almost the whole peninsula under Byzantine rule for the first time since the 7th century. It also created an enduring image of Basil II as a ruthless conqueror, an image that later Greek and Bulgarian national movements each remembered in their own way.