For centuries, the island of Halki (Heybeliada, Istanbul) has guarded a secret beneath its coastline that links the Princes' Islands to the golden age of philosophy. A groundbreaking underwater archaeological discovery has now confirmed a 2,300-year-old mystery described by Aristotle: the waters surrounding Halki were once home to a sophisticated underwater copper mine. This remarkable find not only validates ancient texts but confirms that the island played a pivotal role in supplying rare materials to the most prestigious workshops of the ancient world.
The decisive confirmation of Halki's ancient industry occurred during a recent underwater survey led by Associate Professor Ahmet Bilir of Duzce University. Investigating Çam Limanı Bay on the island's coast, researchers identified clear physical evidence of extraction dating to the Late Classical Period. As reported by Turkiye Today, the expedition team discovered distinctive green copper oxidation staining the seabed and retrieved ore samples from depths of approximately 3.6 meters (12 ft). These findings perfectly align with historical records describing miners working beneath "two fathoms" of water, effectively proving that the island’s submerged geology was exploited by ancient engineers.
The existence of this mine was first documented by Aristotle in his work De Mirabilibus Auscultationibus (On Marvelous Things Heard). The philosopher recorded that divers off the coast of what is now Heybeliada used primitive breathing devices and oil lamps to extract the ore. Aristotle famously noted that this specific copper possessed unique properties, including the ability to improve the eyesight of those who worked with it. While modern readers might dismiss this as folklore, historians note that ancient physicians frequently utilized copper compounds, such as "flower of copper," in various eye treatments, suggesting Aristotle’s account was a factual observation of the trade on Halki.
According to Professor Bilir’s research, the material extracted from Halki was known as “khalkon kolymbeten,” or “diver’s copper.” Unlike copper mined from the earth, this submarine resource was a "niche market product" that commanded premium prices across the Mediterranean. In the religious culture of ancient Greece, the value of a votive offering was often judged by the difficulty required to obtain it. The immense skill and danger involved in diving for copper off the shores of Halki imbued the metal with a spiritual significance, making it the preferred material for high-status religious dedications.
The copper harvested from Halki’s waters likely traveled to Sicyon, a renowned hub of artistic innovation. Historical evidence suggests this "diver's copper" was used by the school of Lysippos, the personal sculptor of Alexander the Great, to create masterpieces for the Temple of Apollo and monuments attributed to Heracles. This discovery bridges a millennia-old gap, revealing that the submerged mines of Heybeliada were once the starting point for a supply chain that created some of the most celebrated imagery of the Hellenistic world.
Photo: Manus AI