A Bulgarian archaeologist announced Sunday that his team had found a gold mask that belonged to a Thracian king in the fourth century BC, near the eastern town of Sliven.

"The discovery of this mask proves that the Valley of the Thracian Kings stretches from the center of Bulgaria to the east of the country," archaeologist Georgi Kitov said.

The Thracians lived in southeastern Europe, the Carpathians and the Caucasus from about 4,000 BC to the 3rd century AD.