But when he came upon the Bosporus he realized what it meant : on the Asiatic shore was a Greek city , Chalcedon . It was they who must have been blind because they had not seen that obviously superior land was just a half mile away on the other side of the Bosporus . But when he came upon the Bosporus he understood : on the opposite eastern shore was a Greek city , Chalcedon , whose founders were said to have overlooked the superior location only 3 k away .