The history of Thassos is rich and very turbulent. The island was occupied by many conquerors who left their cultural traces behind.

There are contradictory opinions about who were the first settlers. The majority of historians consider that the first inhabitants were the Thracians tribes, for example Hedones. However, another group of historians believe that the first settlers were Greeks. Archeologists revealed numerous traces of worshiping the Greek god Herakles as a guardian of the island. 

Herodotus states that the Thracian tribes were the first settlers of Thassos. However they were expelled from the island in 17th or 16th century BC by the Phoenicians led by Thassos. The Phoenicians have built Thassos. They were very skillful in mining, processing of ores, accomplished shipbuilders and sailors. They cultivated the land and enclosed the major cities by walls. Before long the Greek tribes began to colonize the island in large numbers. They adopted the Phoenician knowledge of mining and other crafts. Over time the Greeks prevailed over the Phoenicians and assimilated them.

The opposite views on Herodotus consider that the Thracian tribes attacked the island only in the 7th century BC. The resident Greek population asked the known Ionic tribes from the island of Paros for help. The Parians commanded by Telesiklis managed to expel them. Taking control of the island, Telesiklis, together with his son, poet Archilocus, his family and friend Glaucos began to build and develop the first settlements on the island. Then he advanced towards the neighboring mainland, Kavala and Krenides (former Phillipi) transforming them into the most developed and highly civilized places of the ancient world. Precious metals were successfully exploited. They minted golden, silver and bronze coins with the inscription "Thasian ipiron" (the land of Thassos). Later on, from the year 525 BC, it was the name of the newly formed state. They built temples, and their main settlement was encircled by a marble wall. This wall, unique at the time, was circular in shape and 4km long. They built military and commercial ports and were very accomplished in shipbuilding. Wine, vinegar,marble,ceramics, sculptures and other products were exported.

The Persians, led by King Darius conquered Thassos in the year 491 BC. They destroyed its fantastic marble walls and overpowered the population. The remains of the walls can be seen nowadays throughout Limenass, the capital of the island.

The Persians soon left the Aegean area and Thassos as well. During the period that followed Thassos was seized alternately by the Greek conflicting states Athen and Sparta. At the beginning of the 4th century, Thassos succeeded in reestablishing its state under the old name "Thassian Ipiron".

In the year 340 BC the island became part of the autonomous region of the Macedonian empire. King Filip expelled the Persians and became the king of all Greek people. The Thassos military forces fought under the leadership of Alexander the Great, the son of Filip II of Macedonia, against the Persians, both on the land and on the sea. Thassos maintained its autonomy with few exceptions within the Macedonian empire until the year 202 BC, when King Filip V started to suppress the rights of the Thassos population. They began to turn more and more to the Roman Empire.

In the year 197 BC the Romans invaded Thassos. The island remained under their rule until the year 42 BC. Throughout this time Thassos developed and prospered. However, after the murder of Ceaser (44 BC), two parties (the Republicans, Brut and Casius and the other one led by Marc Antony and Octavian-later on August Caeser) came into conflict. After the defeats and death of Casius and Brut, Marc Anthony was the winner. As Thassos was used as a base for Republicans, the population suffered political repression. Fortunately, this period didn't last for long. August Ceaser renovated Thassos state and gave them back their privileges. The Thassos aristocracy ruled at the time over Sporades. Besides Athens, it was teh only state which had the right to enact laws, to organise its own judiciary and have its own currency. They were privileged to be named "the friends of Ceaser". It was a time of rebuilding. Many old buildings and the old theatre were restored. In the theater gladiatorial combats were held. The remains from the period can be seen nowadays in Limenas and the Archeological museum in Limenas.

The Roman era had lasted on Thassos until the year 330 AC, when Thassos became a colony of the Byzantine empire. Christianity had been gradually established from the year 49 AC on, when Saint Peter had built the first Christian church in Europe, in Philipy near todays Kavala.

In the year 365 AC Thassos was hit by a devastating earthquake.

The Arabs seized the island in 565 AC, but their rule didn't last for long.

From the 7th century on, Thassos was attacked and robbed many times. Robberies and mugging continued throughout the centuries and the population was forced to leave the capital Limenas, and settle down in the interior of the island. From the 10th to 16th century the scarce population that remained on the island, lived in caves, in severe poverty, and hiding. From the year 961 Thassos fell once again under the authority of the Byzantine empire. During the Crusades the island was conquered by Venetians. At the beginning of 13th century the island was being robbed again, this time by Crusaders, Venetians, Spaniards, Sicilians and other pirates. In later times, Thassos was dependent on numerous Frankish rulers, then on Byzantines whose dominance lasted until the fall of Constantinople.

In 1455. Thassos and the neighboring islands Samothraki and Imvros were invaded by Turks led by Mahmud II. Until the year 1774 the number of inhabitants declined drastically from 60000 to 2000 ( the number of inhabitants in the 6th and 5th centuries was around 100000).

In 1813. the Turks gave the island to Muhamed Ali of Egypt as the reward for the Egyptian support in the Greek war for independence.The Egyptian rule was not distressing for the population and the island prospered permanently.

In 1908, Thassos was returned to the Turks.

During the first Balkan war a Greek naval squad managed to unite the island to the Greek state and it remained so until today. Thassos was officially recognized as a part of Greece in 1913.

During the Second World War Thassos and the whole East Macedonia and Traki were under the control of the Bulgarians. The Bulgarians were planning to annex the island to their territory and to carry out forced assilmilation, but they have failed.