Battle of Kleidion

The Battle of Kleidion (or Clidium, after the medieval name of the village of Klyuch, "(the) key"; also known as the Battle of Belasitsa) took place on July 29, 1014 between the Bulgarian Empire and the Byzantine Empire. It was the culmination of the nearly half-century struggle between the Bulgarian Emperor Samuel and the Byzantine Emperor Basil II 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 July 29 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. 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.

Although the engagement did not end the First Bulgarian Empire, the Battle of Kleidion reduced its ability to resist Byzantine advances and can be considered the pivotal encounter of the war with Byzantium. The heirs of Samuel could not subsequently hold off the Byzantine advance, and in 1018 the Bulgarian Empire was finally destroyed by Basil II.