(Al-Kahf) 18 : 83
وَيَسْأَلُونَكَ عَنْ ذِي الْقَرْنَيْنِ ۖ قُلْ سَأَتْلُو عَلَيْكُمْ مِنْهُ ذِكْرًا
And they ask you about Dhul-Qarnayn; you say: "I will explain to you some remembrance of him".
Dhul-Qarnayn (the man of two horns) was a great ruler whose conquests spread from the East to the West. He is referred to as Cyrus the Great.