According to Tafseer Ibn Kaseer, only four kings ruled the entire world. Two of them were Muslims and two of them were non believers.
The two Muslim rulers were: Dhul Qarnain and Sulaiman(AS)
The two non believers were Namrood and Bakht Nasr.
Namrood was the king of the world at the time of Ibraheem (AS). He was a non believer. Allah had given him a vast kingdom and great power,yet he chose to disobey him.He was a cruel, unjust ruler and on top of it , he claimed to be a god and his people prostrated before him.
It is said that when Ibraheem (AS) safely came out of the fire as fire had been ordered to become cool and safe by Allah, he was taken before Namrood. Ibraheem (AS) invited him towards truth and asked him to worship Allah. He said that he was a god himself and asked Ibraheem what could his Allah do. Ibraheem (AS) told him that Allah had the power to give someone life or death.
“Have you not looked at him who disputed with Ibrâheem (Abraham) about his Lord (Allâh), because Allâh had given him the kingdom? When Ibrâheem said (to him): “My Lord (Allâh) is He Who gives life and causes death.” He said, “I give life and cause death…….”
To show Ibraheem that he had power over life and death too, he called before him two prisoners who had already been sentenced to death. He pardoned one while had the other one executed. But Ibraheem was not impressed.
“……Ibrâheem said, “Verily! Allâh causes the sun to rise from the east; then cause it you to rise from the west.” So the disbeliever was utterly defeated. And Allâh guides not the people, who are Zâlimûn (wrong-doers)”
Zaid bin Aslam narrates that an angel was sent by Allah to Namrood to ask him to accept Islam three times. He refused and said that he would gather his armies to fight with Allah’s armies. At dawn he stood with his armies when Allah sent mosquitoes in large numbers. The mosquitoes devoured his whole army and one mosquito entered his nose and kept him in torment for many years. The only way he could rest was when someone hit him on his head. At last he died in this state of misery.
(Albadaya wa Nahaya)