One of the most valuable treasures of the Turkish history is undoubtedly is the Epic of Oguz Khagan or Oguz Khan. Some Turkic cultures use this legend to describe their ethnic origins and the origin of the system of political clans used by Turkmen, Ottoman, and other Oghuz Turks.
According to a Turkish legend, Oguz was born in Central Asia as the son of Qara Khan, leader of a Turkic people. At the time of his birth, the lands of the Turkic people were preyed upon by a dragon named Kiyant. Oguz armed himself and went to kill the dragon. He set a trap for the dragon by hanging a freshly killed deer in a tree, then killed the great dragon with a bronze lance and cut off its head with a steel sword.
After Oguz killed Kiyant, he became a people's hero. He formed a special warrior band from the forty sons of forty Turkic begs (lords, chiefs), thus gathering the clans together. According to later Ottoman tradition, Osman's (Founder of Ottoman Empire) ancestors were descendants of the Kay? tribe of Oghuz Turks.
Oghuz Khan pictured with two horns as Zulqarnayn on a 100 Turkmenistan Manat Banknote.
Image Source: Wikipedia.org