Imperial Vengeance by Ian Ross
The Roman Empire has no mercy in its quest for power.
Aurelius Castus is one of the leading military commanders of an empire riven by civil war. As the emperor Constantine grows ever more ruthless in his pursuit of power, Castus fears that the world he knows is slipping away.
On the eve of the war’s final campaign, Castus discovers that the emperor’s son Crispus aims to depose his father and restore the old ways of Rome.
Castus must choose between honour and survival, and face a final confrontation with the most powerful man in the Roman world, the ruler he has sworn loyally to serve: the emperor Constantine himself.