According to historical sources, Thassos was first inhabited during the prehistoric times. The island was colonized at an early date by Phoenicians, attracted probably by its minerals, especially gold and marble, and of course by the gorgeous forests the island has.
Eventually Phoenician dominance fades and in either 720 or 708 BC, Thassos received a Greek colony from Paros. The Greeks extended their power to the mainland, where they owned gold mines which were even more valuable than those on the island. From these sources the Thasians drew great wealth, their annual revenues amounting to 200 or even 300 talents. Herodotus, who visited Thassos, says that the best mines on the island were those which had been opened by the Phoenicians on the east side of the island facing Samothrace.
In the end of the archaic era, the city is so wealthy that a unique city wall is built, made out of marble and shale, with sculptures on the gates and perimeter of 4 km around the inhabited area. However, the inhabitants of Thassos themselves had to knock it down and pay homage when the King of Persia Dareios and his general Mardonios invaded in Thrace. Later, between 412-411 BC, the wall was reconstructed, but until then the city was almost unfortified.
When between 480 and 478 BC the Persians left the Aegean Sea, Thassos stood again beside the Greek cities. At that time (478-477 BC) the 1st Athenian confederacy was instituted in which Thassos also joined. During the spring of 477 BC, Thassos sends thirty ships in the so called “Delos Confederacy”. But afterwards, on account of a difference about the mines and marts on the mainland, they revolted.
The Athenians defeated them by sea, and, after a siege that lasted more than two years, took the capital, Thasos, probably in 463 BC, and compelled the Thasians to destroy their walls, surrender their ships, pay an indemnity and an annual contribution (in 449 BC this was 21 talents, from 445 BC about 30 talents), and resign their possessions on the mainland. In 411 BC, at the time of the oligarchical revolution at Athens, Thassos again revolted from Athens and received a Lacedaemonian governor; but in 407 BC the partisans of Lacedaemon were expelled, and the Athenians under Thrasybulus were admitted.
"The historical heritage of Thassos is of extreme value..."