No sooner does history become more precise than we are presented with the four great monarchies, that is, with four successful projects, by means of bloodshed, violence and murder, of enslaving mankind. The expeditions of Cambyses against Egypt, of Darius against the Scythians, and of Xerxes against the Greeks, seem almost to set credibility at defiance by the fatal consequences with which they were attended. The conquests of Alexander cost innumerable lives, and the immortality of Caesar is computed to have been purchased by the death of one million two hundred thousand men.