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The Battle of Kleidion, 1014: Basil the Bulgar-Slayer

Byzantine Empire · 29 July 1014 · Byzantines vs Bulgaria · ~6 min read · Updated October 2026

By Echoes of Battle

Fourteenth century Manasses Chronicle miniature of Byzantine cavalry charging and routing the Bulgarians

At a glance

Byzantine EmpireEmperor Basil II
vs
First Bulgarian EmpireTsar Samuel
Date
29 July 1014
Location
The pass of Kleidion, in the Belasica mountains
Period
Byzantine-Bulgarian Wars
Outcome
Decisive Byzantine victory
By the numbers
SideStrengthLosses
Byzantine EmpireA large imperial armyRelatively light
BulgariaA large army holding the passShattered; thousands taken prisoner

Figures are approximate; the number of prisoners is debated.

Quick answer

At the Battle of Kleidion on 29 July 10141, the Byzantine emperor Basil II destroyed the army of Tsar Samuel of Bulgaria, which had tried to block a mountain pass against him. A flanking march let the Byzantines fall on the Bulgarians from the rear2. The sources say Basil blinded thousands of prisoners, leaving a few one-eyed men to lead them home, an act that broke Bulgarian resistance and later, in the twelfth century, earned him the name 'the Bulgar-Slayer'.

For half a century Byzantium and Bulgaria had fought for the Balkans. At Kleidion the emperor Basil II ended the struggle with a victory so complete, and an aftermath so cruel, that it would later give him the name history remembers: the Bulgar-Slayer.

Byzantium and Bulgaria

For decades the emperor Basil II had waged a patient, grinding war against the Bulgarian state of Tsar Samuel. By 1014 Basil was closing in, and Samuel tried to halt the imperial advance by fortifying a narrow pass at Kleidion in the Belasica mountains.

Coloured historical map of the Balkans and Aegean with Samuel's kingdom shaded
The Balkans around the year 1000, with the realm of Tsar Samuel bordering the Byzantine Empire, from Droysen's historical atlas of 1886. Public domain

The trap in the pass

The Bulgarians blocked the valley with a palisade2 and held off the Byzantine attacks. A direct assault on the strong position failed, and for a time Basil's advance was stalled before the wall of defenders in the pass.

The flanking march

Basil sent one of his generals with a force over the mountains to come down behind the Bulgarian position. When this column appeared in their rear, the defenders panicked and broke, and the trapped Bulgarian army was cut to pieces or captured. Samuel himself barely escaped.

A victory so complete, and so cruel, that it became the name history gave the emperor.

The grim aftermath

According to the Byzantine sources, Basil had the mass of prisoners, said to be many thousands, blinded3, leaving one man in every hundred with a single eye2 to guide the rest home. When Tsar Samuel saw his returning army, the story goes, he collapsed, and died soon after3, on 6 October 1014. The tale is traditional and its exact scale is debated4, but it fixed Basil's fearsome reputation.

Why Kleidion mattered

Kleidion broke the back of Bulgarian resistance. Within four years Basil had annexed the whole of Bulgaria1, extending the empire to the Danube and marking the height of Byzantine power. For the emperor it was the crowning victory of his long reign. Meet him, Basil II.

Byzantine miniature of an emperor in armour on a gold ground with angels above and kneeling figures below
Basil II in triumphal armour, crowned from heaven while defeated enemies prostrate themselves at his feet, in the frontispiece of his psalter made in Constantinople around 1000. Public domain

Frequently asked questions

When and where was the Battle of Kleidion?

It was fought on 29 July 1014 in the pass of Kleidion, in the Belasica mountains between modern Bulgaria and North Macedonia.

Who won the Battle of Kleidion?

The Byzantine Empire under the emperor Basil II, decisively.

Why is Basil II called the Bulgar-Slayer?

Because of this victory and its aftermath, in which the sources say he blinded thousands of Bulgarian prisoners. The epithet itself is first recorded in the twelfth century, long after his death.

Did Basil II really blind the prisoners?

The Byzantine chronicles describe the mass blinding, and it became the defining story of the battle, but the exact numbers are uncertain and debated by historians.

What happened to Bulgaria after Kleidion?

Bulgarian resistance collapsed, and within four years Basil annexed the entire Bulgarian state into the Byzantine Empire.

Sources and notes

Numbered notes in the text point to the works below.

  1. Paul Stephenson, Byzantium's Balkan Frontier: A Political Study of the Northern Balkans, 900–1204 (Cambridge University Press, 2000). ↩ a b
  2. John Skylitzes, Synopsis of Histories, Reign of Basil II, the campaign of 1014 (Kleidion, the blinding of the prisoners, the death of Samuel); English translation by John Wortley, A Synopsis of Byzantine History, 811–1057, Cambridge University Press, 2010. ↩ a b c
  3. Encyclopaedia Britannica, “Bulgaria: The first Bulgarian empire” ↩ a b
  4. Paul Stephenson, The Legend of Basil the Bulgar-Slayer (Cambridge University Press, 2003). ↩
  5. Wikipedia, “Battle of Kleidion”

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