Ancient remains in Sapanca Lake may date back to Late Antiquity

SAKARYA

A historic structure with mosaic floors has resurfaced in Türkiye's Sapanca Lake as water levels have receded once again, reigniting questions about its age and origins.

Görkem Işık, an art historian from Sakarya University, said the remains were most likely a small chapel or church dating to Late Antiquity, between the fourth and sixth centuries. “We can date it to what we call Late Antiquity, the period between the fourth and sixth centuries. Both the mosaic technique and the decorative features point to this time,” he said.

With the falling water level in the lake, which supplies drinking water to Sakarya and Kocaeli, the stone foundations and parts of the mosaic surface became visible again. Işık said the structure was very likely a religious one from the Late Antique period. The way the mosaics were made also helped with the dating, he noted.

Işık said the building was almost certainly religious in nature and that its location near the lake shore was similar to the basilica discovered in İznik Lake. He attributed its current submersion to long-term fluctuations in water levels. “In the period when these buildings were constructed, Sapanca Lake's water level was lower. They built the structure close to the shore and expected it to remain there. Over time, the water rose and the building ended up underwater. This is a natural process,” he said.

Residents have also said the lake has seen similar drops in the past. Işık added that changes in water levels over the years are normal.

Only one room on the small islet has mosaic flooring. Işık said this was probably the main worship area. “It is unlikely to have been just a house. Most likely it was a small chapel, part of a monastery or a small church. The mosaic area is the main space and the surrounding rooms were side spaces,” he said.

He added that the structure might have been connected to other Byzantine-era settlements nearby, especially the Byzantine castle in Kurtköy.

Işık also stressed the importance of the remains for the city. “Sakarya never had very large settlements because it is close to major centers. That is why it is important to protect the small amount of cultural heritage that exists and bring it into tourism. This structure should be viewed with that understanding,” he said.

Regarding the pause in the rescue excavations that had begun on the islet, Işık said the work was interrupted for seasonal reasons. “We are in autumn and the ground is very wet. When it rains, it becomes impossible to work. This is a technical pause. If water levels allow in the spring or summer, the excavations will continue,” he said.