The Emperor Caracalla, being with his armies in Mesopotamia, had with him Macrinus, who was more of a statesman than a soldier, as his prefect.  But because princes who are not themselves good are always afraid lest others treat them as they deserve, Caracalla wrote to his friend Maternianus in Rome to learn from the astrologers whether any man had ambitious designs upon the empire, and to send him word.  Maternianus, accordingly, wrote back that such designs were entertained by Macrinus.  But this letter, ere it reached the emperor, fell into the hands of Macrinus, who, seeing when he read it that he must either put Caracalla to death before further letters arrived from Rome, or else die himself, committed the business to a centurion, named Martialis, whom he trusted, and whose brother had been slain by Caracalla a few days before, who succeeded in killing the emperor.

We see, therefore, that an urgency which leaves no room for delay has almost the same results as the method already noticed as followed by Nelematus of Epirus.  We see, too, what I remarked almost at the outset of this Discourse, that the threats of princes expose them to greater danger than the wrongs they actually inflict, and lead to more active conspiracies:  and, therefore, that a prince should be careful not to threaten; since men are either to be treated kindly or else got rid of, but never brought to such a pass that they have to choose between slaying and being slain.

As to the dangers attending the execution of plots, these result either from some change made in the plan, or from a failure in courage on the part of him who is to carry it out; or else from some mistake he falls into through want of foresight, or from his not giving the affair its finishing stroke, as when some are left alive whom it was meant to put to death.  Now, nothing causes so much disturbance and hindrance in human affairs, as to be forced, at a moment’s notice and without time allowed for reflection, to vary your plan of action and adopt a different one from that fixed on at the first.  And if such changes cause confusion anywhere, it is in matters appertaining to war, and in enterprises of the kind we are now speaking of; for in such affairs as these, there is nothing so essential as that men be prepared to do the exact thing intrusted to them.  But when men have for many days together turned their whole thoughts to doing a thing in a certain way and in a certain order, and the way and order are suddenly altered, it is impossible but that they should be disconcerted and the whole scheme ruined.  For which reason, it is far better to do everything in accordance with the preconcerted plan, though it be seen to be attended with some disadvantages, than, in order to escape these, to involve yourself in an infinity of dangers.  And this will happen when you depart from your original design without time given to form a new one.  For when time is given you may manage as you please.