Peter Bietenholz argues that the story of Dhul-Qarnayn has its origins in legends of Alexander the Great that were current in the Middle East in the early years of the Christian era. According to these legends, the Scythians, the descendants of Gog and Magog, once defeated one of Alexander's generals, after which Alexander built a wall in the Caucasus mountains to keep them out of civilized lands (the basic elements are found in Flavius Josephus). The scholar Stephen Gero, sharing similar views, adds that the earliest possible date for the Gog & Magog gate-narrative in this form dates to between 629 and 636, thus tentatively concluding the syriac Alexander Romance "stricte dictu cannot be considered as a source of the Qur’anic narrative", due to the fact that there is absolute consent among Western and Muslim scholars that Surah 18 belongs to the second Meccan Period (615–619). Similar reservations are offered by Brannon Wheeler.