Numedides was the cruel and tyrannical king of Aquilonia until he was overthrown and killed by Conan, who then took the crown from his head and set it on his own. Conan was hailed as a liberator at first, but many people eventually turned against him. A statue of Numedides was put up in the Temple of Mitra where the dead king was revered as a saintly monarch unjustly slain by a red-handed barbarian. The royal minstrel Rinaldo, who remained loyal to Numedides, was largely responsible for this reversal of public opinion through the power of his propaganda songs.
In the later Conan stories, Robert E. Howard altered the spelling of the king's name to Namedides and established that Conan had killed him by strangling him on his throne. This had taken place during a time of civil strife in Aquilonia.