凯撒死后，安东尼和屋大维都怀抱野心，但决定先合作打击布鲁图斯和卡西乌斯。在刺杀凯撒的共和派势力被除掉后，古罗马帝国的内部矛盾日益加剧，各方争夺势力，屋大维和安东尼形成两权对峙。在拉拢元老院各位长老，煽动风向，将安东尼立为“祖国之敌”，向埃及女王宣战等一系列行动之后，为了争夺国家的最高权力，屋大维和安东尼终于展开了海上的决斗。
　　At the Battle of Philippi, Marc Antony and Octavian fight back their joint enemies to lay claim to Caesar's throne. Eleven years later, the two square off in the naval Battle of Actium to decide once and for all the destiny of Rome. The bitter personal rivalry between the two men climaxes when Marc Antony abandons his attacking forces to pursue the fleeing Cleopatra. This single act sounded the death knell of the Roman Republic and gave birth to an empire.