The Cyropaedia (4.6.3) states that a father and son were both reigning over Babylon when the city fell, and that the younger ruler was killed. The Cyropaedia does not name either king, and the silence of other classical sources regarding Belshazzar had cast doubt on the historicity of Daniel's reference to Belshazzar as the king who was slain, until cuneiform evidence was found corroborating the existence of Belshazzar as the ruler in Babylon.[citation needed]