Yoros Castle is perfectly located to oversee the entire Bosphorus Strait, which separates the Asian side of Istanbul from the European side (Rumeli). This strategic position allowed the castle to be a key military outpost for centuries. According to the legend, the castle was built by the Byzantine Empire to control the sea routes and protect the city from invaders.
The Bosphorus was a crucial route for trade, communication, and military movements, and the castle was placed to ensure that no enemy ships could pass unnoticed. It is said that soldiers stationed at the castle would keep watch over the strait, signaling to the city whenever they saw ships approaching. Local legends claim that, during times of war, the watchmen would send messages using smoke signals or fires to alert the people of Istanbul. The castle is thought to have been a key part of the Byzantine defense system, helping to protect the city from attacks. Some stories even suggest that the castle could send messages to the other castles and fortresses across the Bosphorus to warn of incoming dangers. This connection between the castle and its strategic importance in controlling the Bosphorus has been passed down through generations.