"Gates of Alexander" . . . "gates of Alexander" . "legend of the wall" . "iron gates" . . "Barrier" . "Derbent Gate" . . "wall confining Gog and Magog" . "wall" . "Derbent Pass" . "Caspian Gates" . "Gates of Alexander" . . . . "walls of steel" . "behind a great wall" . "mountain valley" . "with divine assistance barred" . "Caspian gates" . "Iron Gates" . "Portae Caspiae" .