Archaeologists date the first settlements in coastal areas of Sifnos in the second half of the 3rdmillenniumBC.The citadelof St. Andrew, south of Apollonia, is an excellent example of Mycenaean fortification in the Cyclades, dating from1300-1100BC.The fortifications of the town seem to have been renovated during the Geometric period, the Classical andHellenistic period.
The ancient town of Sifnos was built on the hill of Kastros and it seems to have been inhabited during the Bronze Age (3200-1100 BC). The island was settled around 1000 BC by Ionians from Attica and, according to Stephanos Byzantios, Alkinor was the ruler of the Ionic colony. The same writer mentions that apart from Sifnos, on the island there were the cities of Apollonia and Minoa. In the city of Sifnos the Agora and Prytaneum, which were built of Parian marble, stood out. There were also many temples dedicated to Artemis Ekvatiria, Enagros Apollo and Epivimios Zeus.
Sifnos flourished in the 6th century BC, due to the gold and silver mines in the Saint Sostis area on the northeast side. With funding from the tithe of the revenue of the gold mines, in 525 BC the Sifnians built an Ionic order Treasury with great sculptural decoration in the sanctuary of Apollo at Delphi.
According to Herodotus and Pausanias, the mines of Sifnos were abandoned very early, probably because they were exhausted, and in historical times Sifnos was not considered a rich island. The legend says that Apollo flooded the mines with sea water, as he wanted to punish the Sifnians because they did not give the tithe to the Oracle of Delphi.
In the mid 6th century BC the wealth of the island caused the revenge of Samians, who destroyed the island because the Sifnians refused to give them a loan of 10 talents. The Sifnians were obliged to pay the Samians 100 talents to leave Sifnos!
In antiquity Sifnos was known for its terracotta vases. Moreover, the Sifnians using reamer manufactured stone containers which when filled with hot oil obtained a dark colour and became very hard.
In historical times, the residents participated in the naval battle of Salamis offering a pentikontoros. They participated in the Delian League initially paying three talents, which were tripled later. In 338 BC Sifnos came under the dominance of the Macedonians and its waters became the theatre of naval conflicts between the Macedonian and the Persian fleet. In 332 BC Alexander the Great drove the Persians away and the same year, according to the sources there has been a meeting on the island between the Spartan Agis III and the Persian general Pharnabazus. Later the island came to the hands of Antigonus and then it passed to the Ptolemies. In 145 BC Sifnos was conquered by the Romans and it flourished.
The historical sources do not provide information about the life on the island during the Byzantine period. We know that, administratively, it was part of the Province of the Islands and its church until the 6th century was part of the diocese of Paros. The capture of Constantinople in 1204 by the Frankish Crusaders brought Sifnos to the Duchy of Naxos under Marco I Sanudo (1207). It was reoccupied by the Byzantine fleet for 35 years (1269-1307), and after a peace treaty with the Venetians the island was ceded to Giannoulis Dacoronia. The last descendant of the house of Dacoronia which was childless was succeeded by Nicholas Gozzadini, son of the ruler of Kythnos and Kea, Angelo Gozzadini. Sifnos was ceded in 1341 by the Duke of Naxos as fief to the noble Venetian Bertuccio Grimani, who never became the lord of the island. Barbarossa in 1537 occupied the island which has been reoccupied again in 1568, during the Turkish-Venetian war by the Gozzadini who were made vassals to the Sublime Porte. In 1617 Angelo Gozzadini was declared to be revoked of his rights and the island was permanently annexed to the Ottoman Empire.
During all these centuries, the population of the island has been decimated by various pirates. The famous traveler and cartographer Cristoforo Buendelmonti in the 15th century describes the lack of men that reached a point where the women of the island could not find husbands. The Sifnians actually paid a special tax, the “turkoteli” attributed to the piratesto secure theirlivesoftheir predatoryraids.
With the privileges granted by the Sultans Murad III (1580) and Ibrahim I (1646), Sifnos experienced a period of economic and social development. As in the rest of the Cycladic islands, the institution of self-government with the election of commissioners was developed. Feature of this period was the foundation of the School of the Holy Sepulchre at Kastros in the late 17th century which operated for 300 students and was known as the Common Educational Institute of Archipelago. Probably Josephus Moisiodakas, the great figure of the Greek Enlightenment, taught there.
The Ottoman rule was interrupted by the presence of the Russian fleet (1770-1774). At the time of the Governor Ioannis Kapodistrias Sifnos was a separate province in the Central Cyclades, and it was an administrative centre of which Milos and Kimolos were part.