There are different opinions regarding the identity of Dhu al-Qarnayn, mentioned in Q 18:83-101. Many claim he is Alexander the Great, and others identify him as an angel or prophet. Many of the stories associated with Dhu al-Qarnayn are drawn from or have influenced the Romances of Alexander the Great.
As for the difference of opinion concerning the reason for his being named Dhu al-Qarnayn of "he of the two horns," it is said: that he had two braids in his hair. It is also mentioned that the two braids were like horns on his head. It is said that at the beginning of his reign he looked as though he was Egyptian with the disks of the sun, and it was explained that the sun would rise and set upon him so the called him Dhu al-Qarnayn. It is said that he was called this because he reached the East and the West as if he had passed beyond the edges of this world. A group of people said that when he reached the rising place of the sun a vision was revealed of the suns' horns so he was called Dhu al-Qarnayn. Others say that had two horns under his turban.