Yoros Castle was intermittently occupied throughout the course of the Byzantine Empire. Under the Palaiologos dynasty during the decline of the empire, Yoros Castle was well fortified, as was the Rumeli Kavağı on the opposite side of the Bosphorus. A massive chain could be extended across the Bosphorus between these two points, cutting off the straits to attacking warships, similar to the chain across the Golden Horn which was used to defend Constantinople during the last Ottoman siege by Sultan Mehmed II.