The King and the Slave — Tim Leach

Ten years after the fall of Babylon, Cyrus's army is on the march again. His slave Croesus, no longer a young man, accompanies him as always, as does the king's son and heir Cambyses, who has inherited none of his father's diplomacy or charisma and all of his vanity and violence.

When the warriors of Persia are unexpectedly crushed in battle Cyrus is put to death, and Cambyses assumes the throne. Croesus, once a king himself, is called upon to guide the young man; but the young man cannot be guided, and after taking offence at an insult by an Egyptian ruler, Cambyses takes the full force of his father's empire to Africa for bloody and brutal vengeance….