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.

• http://en.wikipedia.org/wiki/Battle of Kleidion