The labrys was a religious symbol in the Aegean region from the Bronze Age down to the coming of Christianity; above is a Minoan relief from Siteia on Crete. It may also have been a symbol of sovereignty, since some Thracian kings put it on their coins.
The Odrysians were the most powerful of the Thracian tribes in the fourth century, and their kings had a palace/citadel built by Greek architects. This palace was sacked by Philip of Macedon in 341 BC, and rediscovered in 2005. Above is the foundation of one of the towers of the main gate, which showed evidence of intentional destruction. The citadel is in mountainous terrain at an elevation of 1200 m (4000 feet), and we know from Greek sources that it took Philip's men ten months of tough fighting in the mountains to subdue the Thracians. The archaeologists think they found evidence of Macedonian presence at the site:
Another exciting discovery on the site is a small silver coin minted in the Greek polis of Parion with the image of Medusa, which was used as a medallion of an Ancient Macedonian soldier as the image of the Gorgon monster was believed to have protected the life of its bearer. The archaeologists have found a bronze umbo, or shield boss, of a Macedonian hoplite.Thanks to the many golden treasures emerging from Thracian tombs, Thrace has re-entered our consciousness, and I am glad to read that archaeologists are making other discoveries besides just racing against tomb robbers to secure the wealth of the Thracian kings.