At the eastern edge of the beach of Agios Fokas, a rocky hill enters the sea. It is Vrekastro (or Vriokastro), on the peak of which ruins of fortifications and a settlement from the Neolithic era that date back to the 16th century B.C. have been found. It is the oldest fortification on the island. The swamp that existed around the hill seems to have been an advantage for people to settle there, because it was forested and attracted prey for hunters.
The highest mountain of Tinos used to be called Gyras or Gyrai Petrai after the Gyriaieis, one of the twelve ancient tribes of Tinos that lived there. According to mythology, during the voyage of the Argonauts, when the Argo docked in the area, Zetes and Kalais, the sons of Boreas, the North Wind, and Oreithyia, abandoned the ship and escaped into the mountains. When Heracles heard the news, he climbed Mount Tsiknias and killed them.