There are many legends about the construction of the tower and its location. According to the most popular Turkish legend, a sultan had a much beloved daughter. One day, an oracle prophesied that she would be killed by a venomous snake on her 18th birthday. The sultan, in an effort to thwart his daughter's early demise by placing her away from land so as to keep her away from any snakes, had the tower built in the middle of the Bosphorus to protect his daughter until her 18th birthday. The princess was placed in the tower, where she was frequently visited only by her father.
On the 18th birthday of the princess, the sultan brought her a basket of exotic sumptuous fruits as a birthday gift, delighted that he was able to prevent the prophecy. Upon reaching into the basket, however, an asp that had been hiding among the fruit bit the young princess and she died in her father's arms, just as the oracle had predicted. Hence the name Maiden's Tower.
The older name Leander's Tower comes from another story about a maiden: the ancient Greek myth of Hero and Leander. Hero was a priestess of Aphrodite who lived in a tower at Sestos, at the edge of the Hellespont (Dardanelles). Leander (Leandros), a young man from Abydos on the other side of the strait, fell in love with her and would swim every night across the Hellespont to be with her. Hero would light a lamp every night at the top of her tower to guide his way.
Succumbing to Leander's soft words, and to his argument that Aphrodite, as goddess of love, would scorn the worship of a virgin, Hero allowed him to make love to her. This routine lasted through the warm summer. But one stormy winter night, the waves tossed Leander in the sea and the breezes blew out Hero's light, and Leander lost his way, and was drowned. Hero threw herself from the tower in grief and died as well. The name Maiden's Tower might also have its origins in this ancient story.
Due to the vicinity and similarity between the Dardanelles and the Bosphorus, Leander's story was attributed to the tower by the ancient Greeks and later the Byzantines.
Although it is a legend about the foundation of the city that has come down to us over the ages in various forms, it does not cast any real light on the facts surrounding the initial foundation of the city. According to a local legend which is comparatively much older than the others, the Thracian king Byzas, who was the son of the nymph Semestra, had married Phidaleia, daughter of Barbyzos, king of a region near to Istanbul; it was this woman who is said to have founded Byzantion, or Istanbul.
According to another legend lo, lover of Zeus, the chief of all the ancient Greek gods, turned herself into a cow to esacape the wrath of Hera, Zeus's vengeful wife. During her flight she gave birth to a daughter, Keroessa. on the banks of the Golden Horn. Keroessa was brought up by the nymph Semestra and in due course she gave birth to the son of the sea god Poseidon, whom she named Byzas. Byzas was brought up by the naiad Byzia. and he went on to found the city of Istanbul. It is possible to fit this legend in with the geography of Istanbul. On the other hand, the names Byzas and Keroessa are to be encountered in different forms in very old place names in Anatolia. This perhaps demonstrates that the legend originates in events that took place in the depths of Anatolia's history. According to legends originating in more recent times,(and one of these, born in the 1st century AD, is extremely well-known) Byzas had set out with the chief of a band of migrants from Megara in Greece. The oracle in the Temple of Apollo at Delphi had advised them to set up their new homeland in a place "facing the blind". These migrants were said to have set up their first city on what is now Sarayburnu; this promontory lies opposite Kadikdy, formerly known as Khalkedon, which had been founded 17 (according to other sources 19 or 29) years earlier, and its founders had been accused of being blind because they had ignored the beauty of Istanbul. This last legend must be connected with the Greek migrations that took place between 750 and 550 BC and is certainly not related to the city's initial foundation. The only possibility is that during these migrations anew Greek city was founded in what is now Istanbul circa 660 BC, from which the present city developed.