According to known written documents, Sapanca, which is mentioned as a settlement with the arrival of the Phrygians in the region in 1200 BC, was truly established by the Kingdom of Bithynia in 378 BC. The name Siphonensis Lacus was first used in a Laz language source from 391 AD. During the Eastern Roman Empire, it was known as Buanes, Sofhan, and Sofhange. With the arrival of the Anatolian Seljuks in 1075, the region began to be called Ayan and Ayanköy. After the Crusades, the region passed back to the Byzantines. Evliya Çelebi, who passed through the town on his way to Erzurum in 1640, gave the following information about the town:
Lake Sapanca
Sapanca, Sapanca, Sakarya

