Alexander the Great in the Quran called them the Caspian Gates. Twenty and two Kings did I shut up therein. These pseudepigraphic letters from Alexander to his mother Olympias and his tutor Aristotle, describing his marvellous adventures at the end of the World, date back to the original Greek recension α written in the 4th century in Alexandria. The letters are "the literary expression of a living popular tradition" that had been evolving for at least three centuries before the Quran was written. Several historical figures, both Muslim and Christian, searched for Alexander's Gate and several different identifications were made with actual walls. During the Middle
Alexander the Great in the Quran name Caspian Gates originally applied to the narrow region at the southeast corner of the Caspian Sea, through which Alexander actually marched in the pursuit of Bessus in 329 BC, although he did not stop to fortify it. It was transferred to the passes through the Caucasus, on the other side of the Caspian, by the more fanciful historians of Alexander. The Jewish historian Flavius Josephus (37–100 AD) mentions that: ...a nation of the Alans, whom we have previously mentioned elsewhere as being Scythians ... travelled through a passage which King Alexander [the Great] shut up with iron gates. Josephus