SOFIA, Bulgaria  —  A 2,400-year-old golden mask that once belonged to a Thracian king was unearthed in a timber-lined tomb in southeastern Bulgaria, archaeologists said Monday.

The mask, discovered over the weekend, was found in the tomb along with a solid gold ring engraved with a Greek inscription and the portrait of a bearded man.

"These finds confirm the assumption that they are part of the lavish burial of a Thracian king," said Margarita Tacheva, a professor who was on the dig near the village of Topolchane, 180 miles east of the capital, Sofia.

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Georgi Kitov, the team leader, said that they also found a silver rhyton, silver and bronze vessels, pottery and funerary gifts.

"The artifacts belonged to a Thracian ruler from the end of the 4th century B.C. who was buried here," Kitov added.

According to Kitov, the Thracian civilization was at least equal in terms of development to the ancient Greek one.

The Thracians lived in what is now Bulgaria and parts of modern Greece, Romania, Macedonia, and Turkey between 4,000 B.C. and the 8th century A.D., when they were assimilated by the invading Slavs.

In 2004, another 2,400-year-old golden mask was unearthed from a Thracian tomb in the same area.

Dozens of Thracian mounds are spread throughout central Bulgaria, which archaeologists have dubbed "the Bulgarian valley of kings" in reference to the Valley of the Kings near Luxor, Egypt, home to the tombs of Egyptian pharaohs.